Apple iCloud - advertised as FREE, after you download, you learn it's only FREE for 14 days. That is both misleading and incredibly annoying.
AT&T - why do you have so many log-in pages? You have att.com for combined billing of wireless/internet/home phone, att.net for email, then another log in page for wireless. Honestly!
iTunes - for refusing to allow me to sync my 3G iPhone. Thus requiring me to spend countless hours trying to figure this out, then after frustrating me to the point of writing this post, you suddenly decide to sync. I don't like you today. Furthermore, I don't want to join your PING network, stop trying to force this on me like some kind of crack dealer.