One of my all time lows was Crouching Tiger, Hidden Dragon (or was it the other way round?) I sat through it all because I was with a friend, but I'd lost the will to live after the first fifteen minutes.
I'm sorry to disagree with so many people but I loved Mama Mia. I wasn't expecting much and when we found the cinema was crammed with a mix of middle aged ladies and school girls I was a bit dubious. But it was great! Everyone was singing along, the schoolgirls were all getting up and dancing and we all left the cinema grinning like idiots