
There are several hundred things that annoy me about Outlook. One is that it contains an inferior clone of Lotus Organizer - Organizer was brilliant but for some reason they refused to integrate it with... anything, ever.
Then there's the crashing. Outlook and Excel seem to have a competition of who can go the most wrong this week.
The constant UI nonsense - I dread any updates as they nearly always break my workflow because some intern in Microsoft's soi-disant "design" department decided it would look prettier if they moved everything around and changed the shade of green or something equally nonsense.
I could go on, but I suspect it would be a good idea if I didn't - for the sake of my blood pressure, if nothing else.