When Ты curse, it means Ты don't have any word(s) to say that are appropriate for the siuation you're in.When Ты see people cursing,you think"that person doesn't have anything to say but curse words" and Ты think it's funny.Another theory is that by who it is.Ex:When Ты see an old lady Ты think she's nice and sweet and gentle.And then she starts cursing and Ты think it's funny.