One unforgivably bad thing about OS X is that it completely lacks an appropriate text editor for working with HTML, scripts, or other such text files where you don’t want any formatting artifacts inserted. If you want to see what I mean, open an HTML file in TextEdit, change a view things, and try loading it in Firefox. Even worse, try getting htaccess files properly configured.
Anticipating the response: yes, there are the command line Unix editors – vi, emacs, and that ilk. Even when I used Linux as my primary OS, I was never at some with these infuriating throwbacks to the days of weakly glowing green CRT monitors. Yes, they are very powerful. No, nobody who doesn’t have an intense passion for computer science would ever be justified in putting in the time to learn their byzantine interfaces.
Come on, Mr. Jobs. At least put something like the freeware jEdit into the next version as standard. If you can include the entirety of the child-oriented World Book Encyclopedia, you can spare three megs.