Friends and family have gathered over the fondue pot and everyone’s having a wonderful time, and then you say, a little too loudly, "Well, obviously all people who work in finance are crooks!" only remembering an instant later that the host's mother once worked at Lehman...Cue the record-screech silence. You have caused an awkward moment, yes, and if it’s something you feel strongly about, of course, mention it. If it's possible you might be wrong (halloo, Warren Buffet!), then quickly admit your mistake and ask somebody to pass the wine.