Random chance

An obvious example is where you punch someone and it clearly hits them, but actually hitting the target is based on random chance (modified by possible skills, attributes, or other things) which produces the final did damage, did not do damage or missed graphic/sound effects etc.

For games with sufficient abstraction in visuals, this can be obvious since you don't actually ever see them successfully hitting someone, only swinging/flailing generally. For example, most grid-based games with primitive graphics belong to this. All activity is limited to the character's own grid point and does not extend beyond them, thus they do not appear to hit anyone even if they actually do.

Instances where this is only used for minor things, like critical hit chance instead of actually hitting the target, should not be included.

This is NOT for random efficiency of things (e.g. how much damage was dealt or how much dirt was shoveled).