My identical twin brother and I were both high-level competitive wrestlers. We were the captains of our team, and it was rare that we wouldn't both walk away from tournaments with medals from consecutive weight classes. When you have to fight a genetic copy of yourself, you have an effective grindstone to improve yourself with. I'll be damned if it didn't suck, though. We tried to murder each other. The head coach of Drexel U got to watch us square off once, and he described it as, "Highly intense - almost too serious."