I think it's because you can't have too many widgets, but it keeps freezing up every now and then. Only way the launcher will work right again is by force closing it.
I get frustrated too. If you put too many widgets on the homescreens then the launcher will be slow. There are certain spaces on the homescreen where if you try to put something there it will put it in a folder.
Surprisingly I am not too angry with this, Launcherpro works and I know Ice Cream will completely change the look of the launcher so I am fine waiting, only a couple of months before we get Ice Cream.