The worst curse put upon us is XNA games engine, which was unable to distinguish primary from secondary clicks. So players who swapped mouse buttons at the OS level were out of luck.
Most developers assumed that left click = primary click, but that's only true about 95% of the time.
Most developers assumed that left click = primary click, but that's only true about 95% of the time.
Terraria, among others, still has this bug.