Measuring ones self by others.
One of my Facebook friends posted a good article on thoughts about being worried about what others think of you: http://hellogiggles.com/worried-other-people-think/
Oh so true, but I'll add to it - none of us are as important as we think we are. A great way to realize that you are your own best friend/conversationalist/person is to, whilst in the middle of a conversation at an event where many people are talking, simply stop, cutting your sentence in the middle. I can guarantee that most of the time not a soul notices (very humbling - not depressing if one realizes that others are so insecure that they are readying in their minds their reply thus totally not listening to whomever is speaking). Or you're telling a story and some one interrupts: I can again guarantee that 95% of the time no one comes back and say "please finish the story". Which is why the best conversations happen when one person has the grace and courtesy to actually be interested in the other person's conversation and to listen, really hearing what is being said - there is great merit and lots to be learned by being that listener.
As some wise person said (sorry I forgot to whom I should attribute the saying) “You are the only person that you will live with for your entire life”. Most of us are so wrapped up in worrying about what others do, or might, think of us that we forget to ask the most important question: what do I think of myself?