I thought the A and B buttons actually reduce damage taken and improved damage dealt in Pokemon battles
B-but they do!
Spoiler:
I tested on some rpgs, you can create an save state, then try to change the results pressing buttons. Iff i choose to do nothing the result is always the same(which means the result is calculated during the attack/ability use), but pressing buttons i can change the result, i demand that mythbusters explain this.