Physical Danger

Physical Danger

 
After vanquishing countless armies of dragons, assassins, warlords, hell beasts, and super soldiers, XxXBob43 was finally defeated by...poor, yet correctable wrist posture. (Source)

Dangers in real life won't be anything like the ones you'll face in your games. If you fail or lose, nobody's going to actually blow your head off or lob a grenade your way.

However, carpal tunnel can be a serious problem, especially amongst gamers who play high APM (that's actions per minute) PC games like StarCraft.