I know exactly what you're talking about. I had a "fun" moviegoing experience not too long ago. For the first half of the movie, a kid next to us was hollering and crying, making a general fuss over what mom wouldn't buy him at the candy counter. While that was going on:
Three spilled beverages, one of which had my foot stuck to the floor at the end of the show
Two spilled packages of something hard, round, and noisy as they rolled from the back of the theater down to the front
The couple in front, who weren't too awful bad, but could've been a little quiter while discussing the gripping dialogue
And the highlight: the non-English speaking family directly behind me. Mother was translating the entire movie into a language I've never heard before.
After later buying the movie on DVD, I saw that I'd missed most of a pretty good movie. :-(