What do you think of people that go around quoting other famous people?

If I am talking to someone, I would prefer to hear what they have to say and their opinion without them trying to reinforce a point with a quotation from some absent person. Occasionally, it is nice to be reminded of something inspiring, but some people rely totally on quoting others and they have an arsenal of quotations to bombard you during a conversation. Anything from, Obama said or, Einstein said or, Churchill said, or my Dad said; and sometimes when they can't remember the source they will say, A great man once said. What's your experience? Do you know people that have this trait?