Yup, good point – I need to do this more often.

Being in safe mode, you would have been able to solve that problem without restoring. In fact, if you have SSH installed on your device, you can fix almost any problem without restoring. If you dont know how, you can always ask the author for help or join some of the support IRC channels like #iphone on irc.osx86.hu. There are people that will help you.

A lot of people jump to the conclusion "I had to restore" when they did not have to restore.

Also, Apple does not do any extensive review. Their process takes a lot of time, but apps with bugs get released all the same. The reviewer spends a few minutes with your app and if it "looks good to me" then it goes live. They compare it to a checklist of things not allowed, and if it does any of those things, it's declined. DO not be fooled into thinking that there is some rigid quality control in Appstore. There is not.

Reporting the app to the repository owner and the devloper (at the same time) helps a lot. As a repository owner, if I get enough reports in a specified amount of time on a crashing app, I take action. If the app causes springboard to crash or something more serious than "dont tap the icon to run it then", I will take action quickly.

As always, a great contribution to the discussion, thanks. I agree with much of what you've said, though not all. You got it right on the main point of the post. I do think there are a number of newer jailbreakers, or would-be jailbreakers who are not very tech-savvy, or who have no desire to take the time to become tech-savvy. That's fair enough – nobody is a lesser person for that. And I believe a lot of those users will not want to 'mess with' figuring out which extensions conflict with which others and so forth, they'll just either opt out of ever doing a JB, or run from it fairly quickly when they see these issues.
Thanks for the further take on how to think of extensions – think I've got it now.
I think one of the trickiest parts of all of this is that whole bit about being very careful about which apps and extensions you install, to ensure max. stability. That's a principle I tried for a long while to follow. Of late, I've not been so good at it, and that's probably the single biggest factor leading to having some more issues recently. But … quite often the apps that most interest me are the ones that do not look like the safest bets, the ones that do require something via mobile substrate, that do interact with springboard etc. Most of my app switching and multitasking apps fall into this category I would say.
On other occasions, just the fact that I'm a reviewer / writer on iPhone apps leads me to try out apps that I don't have enormous interest in in terms of my own personal use. Front Contacts is an example of one of those. I'm not a heavy enough phone user for it to be hugely useful for me – but I find it a potentially attention-worthy app for JB users in general – so I want to give it a go (and in fact I am, for the second time, the last few days).
The more I think about it, the more I think mobile substrate's Safe mode is quite a handy thing, but I still think less 'dedicated' jailbreakers will likely not see things that way.

@All: The point of this blog post was not that Patrick is scared of jailbreaking, has no experience doing so, or does not know the merits of having a jailbroken device. As he explained in this post and has shown in countless other posts, he has been jailbreaking for a very long time. The point, I believe, that he was trying to make is that the vast majority of iPhone users in the world are not technical people. They do not want to spend ANY time researching apps before trying them to find all the reviews that explain whether the app is stable or not. They do not want to spend ANY time trying to find a solution to problems they are having due to conflicting MobileSubstrate plugins. They want their device to just work. Always, and without any thought. Jailbreaking is not for everyone and never will be. It shouldn't be. Patricks point was these very issues do drive people away and give the scene bad press. These (rare or not) crashes and other user experience effecting issues do indeed drive users away and give cannon fodder to the press and other parties that are interested in showing how evil jailbreaking is.

Those of us with a great deal of jailbreak experience know that if you are very careful in which jailbreak apps and extensions you install, you will have NO problems. Your phone will be just as stable as it was before being jailbroken. That is a simple fact that a very large number of people are not able to grasp. They see something on Cydia and they install it without a seconds thought on what performance impact it may have. Then when things start crashing, they just restore and start over instead of attempting to narrow down the one app or extension that was causing issues. Patrick is not saying jailbreaking is bad. He is saying he believes people in general are just not interested in putting any effort into keeping things smooth. I absolutely agree. These issues turn people away from jailbreaking, and that's a good thing. They are the type of people that should not be doing it in the first place.

@ashikase: Your contributions to the community are well appreciated and your comments were spot on. There is no easy solution to the problem such as more testing or better control. The solution lies with the end user. If they just want everything to work without the possibility of any issues, they should not jailbreak. If they are willing to put in a little effort and put up with some conflicts and spend some time working through such conflicts, the jailbreak world is their playground.

@Patrick: Think of an extension as anything to changes the way any other part of the phone or software works. If it slightly tweaks your address book or the way something else looks, it's an extension. If it does anything outside of its own self contained little sandbox, it's an extension. If it is completely self sustaining and doesn't touch anything else (Springboard, ringtones, contacts, lockscreen, ANYTHING), it's an application.

@Bryan, John Steele, and metalheadreview: You do not EVER need to restore. If you spend a little time there are many many guides that explain to you how you can disable extensions that are causing issues to get your phone back to a working state.

You don't see crappy apps in the app store? Really? There are an insane number of crappy apps in the app store. There are also apps in the app store that do cause crashes. I will not argue that Cydia isn't somewhat of the wild frontier and could use some better control and organization, but in my opinion this is far from a reason to support Apple's TERRIBLE review process.

I run a bunch of jailbroken apps and little UI things. I started noticing that the livetime mod that changes your clock icon to a live LCD was crashing my 5 icon dock and springboard when I clicked the iPod icon. Once I figured out the cause, I disabled it in Winterboard and now my phone is stable as ever.

I do think an indication of which are extensions would be helpful – because I have to say that something like iAccounts does not feel at all like an extension. I understand the reasons you state why it is, but for a user, that does not seem intuitive at all. The idea of user accounts on the iPhone is brand new, it is not extending an existing concept or capability etc. – doesn't 'feel' right to call it that, while it may well be technically right.

But you also don’t get the good apps.

iRealSMS/BiteSMS and ProSwitcher (and Backgrounder) are the two main reason iPhone should be jailbroken! Try them, they are wonderful apps.

IAccounts and AnyRing are both extensions (or, at least, include an extension component). Front Contacts is a lockscreen widget that uses Cydget, which is itself an extension.

Normally anything that requires mobilesubstrate is an extension (technically apps *could* require it, but there would be little point).

Perhaps what is needed is a way, in Cydia, to show if a package is an extension or an application. The trouble, though, is that it's possible (but not recommended) to make extensions without using mobilesubstrate, so while one could say that "this is an extension as it requires mobilesubstrate", that statement would not catch all extensions.

Here's the deal though – it's also the equivalent of a mode a new jailbreaker has likely never seen on their stock phone, and likely one they don't fancy seeing again. One of the apps you might want to install is a spellchecker – so when you want to spell happy or gay or whatever you were going for, you perhaps come somewhere close.
As for noobness, yeah guess you've got me there. As I said in the post I've only been jailbreaking since 2007 / the first ever jailbreaks. You sound far more knowledgeable.

I've never said I was worried, and it is not a reason not to jailbreak for me / for experienced users. But … I think this is definitely a reason why less experienced users would shy away.

In the absence of that community vote, I think posts like this help bring some of this discussion to the table – or I hope they do anyway.

Hmmm. IAccounts and AnyRing strike me as apps, not extensions. Front Contacts may be an extension – I'm not sure.

And yes I'm sure there are no easy solutions – I was just passing comment on the fact that things like this will not encourage newer jailbreakers to stick with it.

I do not use any of the jailbreak apps that you have listed, but I have a ton on my iPhone and I do not see any stability issues at all. It all comes down to the fact that jailbreak apps have little to no quality control and there is also not a good community review system for them. If an app is released that crashes an iPhone, there should be a way for the community of users to vote it down until it gets fixed.

One thing to keep in mind is that MobileSubstrate’s Safe Mode is simply SpringBoard without any extensions loaded – in other words, it’s like SpringBoard on a non-jailbroken device (albeit with a grey background). And while crashing is never a fun experience, we should all be thankful to saurik for creating Safe Mode… without it, a bad extension could cause your device to wind up in an endless restart-loop.

As for beta-testing, it does not always work. It can be difficult to find people that are actually willing to report feedback; often volunteers simply want “the latest version”. There have also been cases where testers have leaked beta versions to the public, which ended up causing trouble for end-users and support requests (and headaches) for the developers. Believe me, I wish there was a proven beta-testing system in place; no matter how much I test my software, I always worry that I might have missed something.