One of the finest arts one can learn and do well is acting. To be believable in a role, one must put oneself into a role totally and completely. It has to be something the audience will buy, right? There is a right way to cry, to laugh, to fall, and to get punched in the face. If a punch in the face looks put on, no amount of sound effects will cover up the fact that a guy’s fist was clearly not in contact with the other guy’s face.
Take a look at this great montage containing 100 of the best punches, slaps, and kicks in the groin captured on film. (Props to @Live_for_Films for this great find!)