You are your worst enemy when you allow others’ opinions of you to be more important than your own.
You are your worst enemy when instead of facing problems and learning from them, you bury your head in the sand.
You are your own worst enemy when, with the excuse of being demanding and perfectionist, you are self-flagellating and too hard on yourself.
You are your worst enemy when you neglect yourself to help others.
And no, it is not selfish to take care of yourself first. What is selfish is not to do so.
Because if you don’t take care of yourself, you won’t be able to help others.