There are lots of jobs where I think, "I could do/could have done that"; Acting is one of those artistic skills that when someone does it really well, when they really disappear into the role (not DeNiro's version of whatever, which can still be compelling and great, mind you) I am amazingly impressed. The folks who disappear inside those roles, I could never do that.
They worked together on these movies for years and I am sure they remain great friends to this day; why does that imply teh ghey to some folks? Not that there is anything wrong with that.