I'll tell you something I hate. It's when you think you've dealt with something and it turns out you haven't. Not through any fault of your own but because of someone else's delinquency or inefficiency. They told you it had been taken care of and it hadn't. You gave the information and they copied it down wrong. They told you nothing needed to be done when something did need to be done. You and they agreed a course of action which they haven't followed up on and it all has to be discussed again. I hate it.
Why do I hate it? Simple - you never know where you are. Things long crossed off your list have to be put back on it. What's the good of having a list if it's always in jeopardy like that?