We're all odd old things, as you say.

We can only get away from that depressing fact by doing something, and not thinking about ourselves.

We can all try not to be egoists.

Egoism is the really heavy quality in the world." She paused a moment in this inspired discourse and whistled to Og, who had stretched his weary limbs across a bed of particularly fine geraniums.
"There!" she said, pointing, "if your dog had done that, you would be submerged in depression at the thought of how vexed your father would be.

That would be because you are thinking of the effect on yourself.