My attitude at the beginning was "well, it's a nice little program, does my mail, does my calendar. Cool. What's the problem?"
The problem, as it turns out - or one of the big ones - is that Outlook will once in a while (say, once a week) decide "Well, you don't get to do any more work right now." and consume all of my CPU until I kill it off and restart it. Grargh.
On the other hand, this is one of the most awesome things I've seen in at least a few days:
For some reason, I'm thinking of Stefan and Adam when I see this.
...So it appears one of the causes for the Outlook problem was that someone sent a 286 KB attachment to a 1500-person mailing list. Twice. Outlook tries to download the message at the same time as everyone else, and croaks. RAGE. I'm going to make quite sure the person in question knows that this is a horrible idea.