Michigan Stadium is widely recognized as one of the least intimidating large stadiums in the US. Part of it is due to the design of the stadium -- the seating is very flat and shallow, allowing most of the noise that the crowd makes to escape. Part of it is also that Michigan alums are all wealthier and better-behaved than their counterparts at Ohio State, Tennessee, Florida, Florida State, LSU and other places.
Now, it appears that Michigan is going to add luxury boxes to its stadium. Le sigh.