I think that’s one of the BIG things perhaps.
For me the mouse has always been a rather nice direct link to the interface. But if you have learnt to be able to do almost everything from the keyboard I guess that could be a cause of some frustration.
Correct me if I’m wrong but you can’t select from the “source” window in Avid and drag a a clip into the timeline with the mouse? Maybe I was doing something wrong but I found that immensely frustrating when I was playing with the free trial.
Even in X I occasionally dump something at the end of the timeline that I know I want to use later. Probably bad practice but it works for me.