There are certainly some programs that interrupt you before you do something stupid “Are you sure you want to quit?” but typically these dialogs simply slow down your workflow. I love it when I find one that is really keeps me from doing something stupid. Case in point: select 40 or so e-mail messages in thunderbird and hit return, at least on the mac you get this friendly slap on the wrist:
Just after realizing that I didn’t hit the delete key and instead hit enter, and right before I thought “oh crap opening 52 messages will be slow,” there came thunderbird to my rescue. Thanks thunderbird.