The only two we've left were because of an antsy toddler - Brave and Rise of the Guardians. She now loves Brave, but I don't think any of us were enough invested in Guardians to care.
I haven't left any movies (to date) because they were so bad - but I do have a habit of embarrassing the crap out of my husband by laughing at things that I find insanely bad, even when they're not funny. Spiderman 3, when he was doing the emo b.s.? I laughed a ton. That stupid scene in Pirates 3 where they're fighting on top of the rolling wheels things? Almost got kicked out. I almost had to go to the lobby for whichever X-Men movie had Kelsey Grammer in blue face paint and fur.
This reminded me of a scene in Pearl Harbor. The main characters are at a filling station or tarmac and the acting/dialog was so hokey - somehow I was instantly feeling like it was a scene in Airplane, waiting for some reference to George Zip or Striker.