One thing I have noticed about how some people here wear their caps is, that they pull them down too far onto the back of their head. The reason the caps from Hat People are puffing up is for that reason. Try pinching down on the front of the cap and bring it down onto the bill. Then place the cap on your head while maintaining the pinch. To do otherwise will create the mushroom hat. Unless that is what you prefer of course. The back of the cap shouldn't be near the back of your neck, or touching your ears.