Very minor gripe but took DS to the cinema yesterday and we arrived about 5 mins before the film was about to start. The cinema was pretty empty and the whole front left section was free (about 8 rows of seats) so we sat at the back of this section. Just as the film starts a woman and her DD arrive and out of the whole empty section, sit in the seats next to us. The way this cinema works is you get asked where you want to sit, so why wouldn't you want to enjoy spreading out and having a whole row to yourself rather than choosing to sit right next to someone else in an otherwise empty section.
This also happenned on holiday last year. DP, DS and I went to Wales and found a lovely deserted section of beach to sit on, and another family proceeded to sit about 10 feet away from us on a beach that was otherwise empty for miles.
Sorry, I know this is very minor but was a tad annoying at the time.