The final major thing that "I Don't Like About iTunes and iPod" has annoyed me from Day One: the monolithic bloaty binary library, and the accompanying tidy-but-inefficient XML backup. For a small library, it's no problem, but mine has major issues. Heck, and I don't even consider my ~40GB library to be particularly big!
iPod Video Conversion in iTunes
The kludginess of video conversion for iPod in iTunes is another one of the things "I Don't Like About iTunes and iPod". I don't like the conversion process, and I particularly don't like the bug I think I've found.
Mac Flight Tracker widget timezone bug
The Flight Tracker dashboard widget that comes with Mac OS X 10.4 (Tiger) seems to have a fairly major bug. However, this bug seems to be the result of something quite obscure to do with timezones, and it only seems to manifest itself in the UK during the summer.