There is always going to be some person that you find wandering about the club looking like they're going on an adventure or they're too drunk to find their friends and walk in a straight line. In that case, they'll probably join your group of friends on the dance floor and because they're so involved in the group, you'll assume that they're someone's friend or relative. It isn't until you get out of the club and everyone asks each other who that guy was that you realised how easily trust can be gained and then broken.