1. Tools-->Options-->Show Passwords-->Show Passwords WTF? I should have stopped using firefox when someone showed me this for the first time.

2. The real last straw was Firefox's support for EV(Extended Verification) certificates. I can't find any solid information if they will be supported in FF3, or even when FF3 is scheduled to come out. I found this post, but this kind of attitude of denouncing a decision after it has been made rather than trying to help the process really bothers me. 

3. Auto update. I don't know why firefox updates in the background and then gives me a crap dialog box to "install now or later" nagging me every time I start it. Did they get bought out by Adobe?

4. Firefox still has memory problems. If I surf for 2-3 hours, opening a lot of tabs, and then trim down to 2-3 base tabs Firefox will still be around 200meg.

5. Buggy CSS. As much as firefox fans crow about how good their CSS is, there are still way to many bugs/inconsistencies.

6. Too many versions. There are too many versions and no clear road map. We don't really need 2.0.3, and all the versions give fan boys a crutch, "Well, have you updated to 2.0.3a? That will fix your problem"

7. Firefox crashes too much. I'm on my computer all day on XP and Server 2003 and programs don't really crash anymore. Sometimes I kill them, but Firefox crashes at least once a month.

8. Too much blame on extensions. Any problem with FF is shoved off to "its probably an extension". Extensions should not be allowed to crash the main program.

9. If I open a new tab and type the url too fast, it does not work. This, surprisingly, is my second biggest reason for leaving Firefox. I used to be able to Ctrl-T, and start typing. Now when I try the cursor is in the address bar blinking, but typing does nothing. I have to lose focus of the address bar and then put it back in.

10. If I have too many tabs open, copy/past breaks. That is, I cannot copy from Firefox to another app. I can copy from notepad to another app, but not Firefox. I cannot reproduce this on purpose, so I don't know for sure it is FF, but I suspect.