You are not perfect. You do not know everything. You never will.
This affirmation is all about humbling yourself and making sure you are constantly motivated to better yourself.
If you're the smartest guy in the room....Find a new room!
Meaning, always be looking to learn from others. Never be content with your level of knowledge. If you're content telling others in that first room how much you know, and never leave that room, you've become complacent. It's awesome to share knowledge and guide others in the right direction (heck, that's what I'm trying to do right now), but that is a room you should come back and visit. We do not want to spend all our time in that room. Find new rooms, with new teachers, and new subjects.
An ego is useless.