How can a movie be too long?

Yglesias and I live in different worlds:

I went to see Public Enemies last night. It’s pretty good. Stylish, elegant, well-acted, but a bit on the dull side—for some reason Michael Mann seems obsessed with trying to drain the excitement out of pitched gun battles. But even that wouldn’t be such a problem if not for the fact that the movie just seems way too long.

This is, it seems to me, a surprisingly common problem with would-be summer blockbusters. And it’s a problem I have a lot of trouble understanding. After all, movie studios would seem to have a strong incentive to make movies shorter. With a shorter movie, you should be able to pack more showings into a given day and sell more tickets and popcorn and such. And yet I feel like it’s way more common to walk out of a theater feeling that a movie was too long than to walk out feeling like I wished there’d been 15 more minutes. I don’t think I’m alone in this feeling. So what’s going on?

I very seldom go to theaters (Iron Man was the latest), so maybe there's something about being cooped up with bad, expensive food for long periods of time that eventually grates on people. But in watching only well-reviewed movies from the comfort of my home--as I do, with intermissions whenever we please-- I almost always feel the story was rushed and should be hours longer.

But then, I am guy who sets aside 3 days every year to watch all of Star Wars, Indiana Jones, and Lord of the Rings. So I gotta figure I'm the oddball.

Anyhow--in honor of long movie-watching experiences--I give you a nice chart by Dan Meth: