The worst thing was Nintendo Palm. Back in the N64 days, the Mario Party games had these games where you spin the analog stick as fast as you can. The best way was to put your palm on the joystick and spin it around. I personally never got a bad blister, but it would hurt your palm. I knew 2 people who got bad blisters from it though, and started playing with gloves 
My hand does get cramped up with the DS though, even if I'm playing slow games like Advance Wars.








