At some point I either read somewhere or some authoritative-type intellectual told me that we are actually less ourselves than we are something else. I think this is a pretty sweet little factoid, so I occasionally unleash it on an unsuspecting friend or acquaintance at a social function. It's my go-to zany science sound bite. It goes something like this.
Defining the self is not, under normal circumstances, in the generalized wheel-house of science. Red blood cells? Check. Liver, spleen? Check. Personhood, the self, the soul? See philosophy. If science were forced to say something about the self it might come up with this: we exist as the genetic material which programmed our development. Where do I exist? I exist in my code, in my unique genetic fingerprint, in that which differentiates me from every other living organism. So we start there. The thing that is us in our body is our genetic material.
Here is the kicker. There is more genetic material in my body (and yours!) belonging to other creatures than there is belonging to me. This is because there are ten times as many bacteria in the human body as there are human tissue cells. Isn't that neat? You are more not you than you are you.
Next time you are yelled at by a loved one for goofing up just remind her (or him) that you are not yourself. You are actually mostly something else.