I think its natural for people to communicate via comparison... to make themselves relateable, to offer advice, etc. As you can see, almost everyone has responded with a similar story/anecdote, but i think most of us can tell that no one here is trying to maliciously one up you. I notice I do it sometimes too (and I'm doing it now

), but I've gotten better at consciously stopping myself and asking whether the person I'm talking to needs someone to vent to or is genuinely asking for help. Sometimes the conversation is more natural, less stagnant, and spicier when each person is adding something rather than waiting for the other to finish to politely ask questions.
Where it gets annoying is when the person literally cannot respond to anything you say without making it about them. I had a "friend" like that in college, and at some point I would just stop responding and let her have a conversation with herself. Eventually she got the hint, and we're no longer friends. (Although she does try to facebook chat me occasionally, to ask me how I'm doing, and when I respond? She tries to one up me. Some people never change.) I think perpetual "one uppers" are socially awkward, very insecure, or painfully self absorbed...probably usually a combination of all three.