My number one hate is the colour handling and colour previews (for print). No where near 'pro' at all. Pdf export can embed profiles but you can't see what they look like.
Everything I do has to be checked in photoshop and then tweaked and exported again. Some times quit a few times especially when using gradients (which I also do a lot)

There is still a bug with preview and grouped shapes If it is on I get wierd banding. - this has been reported a couple of times.

My number 2 hate is the fact that I can't see the line colour and the fill colour at the same time in the colour editor. This is a real pain when tweaking colours - which I do a lot.