Adrenaline Shortage?

I saw Mission Impossible III last night and I have to say, I really enjoyed it. So, Tom Cruise is a little quirky. Every now and then it's just fun to see a movie with a pulsating theme song, non-stop action, fast cars and multiple explosions--you know, the ones where you just sit back and enjoy the ride and get the most out of the theater's big screen and surround sound. I left the theater wanting to re-watch the first two Mission Impossible flicks and fought off a slight craving to blow something up.

I sometimes wonder if I have a shortage of adrenaline since I so enjoy-- even crave-- the rush of action and horror flicks, ghost tours, roller coasters, prefer deadline pressures in my employment choices and consume constant coffee and Diet Coke to wake up in the morning. Yet, if a spider runs through the room, all the fun is over and I'm ready to run from the house screaming.

Is this a vitamin deficiency? Personality disorder? Mental illness?

What is my problem?