The first thing about Twitter is; there are no rules. No user guides to agree to on sign up. You can report someone for spamming you (sending repeated unsoliciticed messages, whether you're following the account or not), but you cannot report someone for being rude, obnoxious, irritating or having a bad day.
This is my very personal top 10 of things which wind me up on Twitter. I'm allowed a negative post every now and again, and I think we're running on a ratio of 1:9 at the moment. There's a mix of business and personal account gripes here. Not everyone will feel this way. (I think I've slapped enough disclaimer stickers on this now).