What you and your bike are actually capable of.
That you have a LOT to learn. And always will.
Humility and respect for the art of riding and, just as important, physics.
How your bike behaves at speeds you cannot achieve safely on public roads (and yeah, it's very different).
That what felt fast on the street... isn't.
That your brakes can make you go
The importance of consistency, smoothness, precision, vision and planning.
That any monkey can twist a throttle, but it takes real skill to go fast in the corners.
That being a perpetual student brings great advantages.
Edit/add: That your bike is smarter than you are, and it's wise to get the hell out of the way and let it do its thing.