Do our thoughts become us?

Sometimes I think that if others could actually hear my thoughts they would look at me as a completely different person. (Probably in a negative light.)

Do you believe that we are manifestations of our thoughts and ideas, or is it more complicated than that? For example, if someone asks me to look at his baby pictures, I might be thinking, “Oh, great…more boring pictures,” but I might look at them and be genuinely interested.