Smith gave a perfect example... other things I have seen over the years include tourists who pick fruit out of people's trees without permission, taking someone's pet thinking it was a stray, taking pictures or videos of private moments without permission, creating expectations by throwing money around to the point that one is perceived to be "buying" friends, getting confused by the patois to the point the tourist agree's to something they shouldnt have... that one actually happens quite a bit...
And then of course there is the obvious venturing into places or establishments that even most locals avoid, especially at night... there are more, but they can all be avoided by having someone with you who is watching out for you and your party!