If the thrill is gone, you are blasé. If you yawn on a roller coaster, then maybe you've had one too many rides.
The adjective blase (most often spelled blasé), describes someone who is bored with the pleasures of life because of frequent indulgence or exposure. When asked what she thought of the award ceremony, the actress yawned and replied, "It was blasé. It was just like the last 15 award ceremonies I had attended."