I can't rewatch Hamburger Hill, Band of Brothers, or Saving Private Ryan. Some of the scenes in those movies are just too intense. I also won't watch Toy Store 3 or 4 again.
I probably won't watch Green Mile either.
As for animal shows, won't watch if something happens to them. Have never seen Old Yellar, Bambi or Dumbo, just can't do it. Couldn't tell you how many times I've seen Lion King but I've never watched the scene when Mufasa dies, I either look away or walk out of the room.