I think what you're "feeling" is a simple matter of disconnecting your UI thread from the "do stuff" thread. It's not the waiting that aggravates us most, it's the fact that the waiting bits drastically slow down, if not disable our ability to do other things in the meantime.
I think you are right. If I have several application minimized under windows and I try to go back to one app after few hours it not only takes a long time to maximize its stop everything else from working. The performance get worse as you use your computer longer. I remember my fresh window7 install was a nice change over vista but it has gone worse in last few months and it gets slightly better every time I defrag HD and register, it gets worse again after few weeks/months.
This never happens on OSX. They are obviously doing something right.
