Of adrenaline and testosterone that fuel excessive agressive competitiveness

I'm competitive. Fiercely so. Boggle, Scrabble, floorball, football...any game, basically, will induce my adrenal and testosterone glands to release a flood of hormones into my system. Just a few hours ago, I was attempting to engage in a friendly, non-competitive game of badminton, albeit unsuccesfully. Before I realized it, I was setting up a competition to see how long we could keep the shuttlecock up for. Then I was smashing at innocent lobs like a crazed lunatic (thought most of them either went wide or fell flat on their faces. Literally. ;p) Then I caught myself. For goodness sake la, Joel...it's just a game! A passing comment by a friend jolted me to my senses. There he goes again...Joel is like that one. OUCH. Hehe...
It's like I go on autopilot whenever I engage in any sport or recreation. I naturally slip into "compete" mode and feel unfulfilled if there is no kind of incentive or goal to work toward. Is it a guy thing? Male machismo, primal instinct? I wonder. You tell me.