1. Logging into Battle.net. I have no clue why, but this has consistently been one of my worst experiences with Blizzard. I have no clue why, but I generally fail 20x before I finally get into the site, using the same login info and my security token. It makes me think my token is faulty, but it has never given me issues in game.
2. Chat support windows that are supposed to open in a new window but don't... even though popups and java are allowed.
3. My life.