Roger Ebert sacrifices a tiny shred of journalistic diligence for the sake of his own sanity:
Q. How can you give a one-star rating to a movie you didn’t sit through?
A. The rating only applies to the first eight minutes. After that, you’re on your own.
I still hold a grudge against the New York Times critic who walked out of Dawn of the Dead in 1978 after only ten minutes. It seemed to me that just sitting through the damn movie was the only part of being a movie critic that I was sure I could do as well as anybody.
For what it’s worth, conventional moviemaking wisdom gives a typical movie three acts, with the first act taking twenty or thirty minutes. I’d consider that the bare minimum to form an opinion. But some of my favorite movies are ones that somehow subvert in an interesting way the expectations set up by the first act.
Anyway, although I grant Ebert permission to save himself from needless suffering at his own discretion, I know I spend at least a couple of hours in every work day doing less pleasant things than watching bad movies. So I’d like to sympathize, but I don’t.