“Novice fans don’t understand it. Longtime fans claim to understand it, but then openly disagree about it. Referees and their assistants are trained to spot it, but often have to turn to replays to make sure they’ve got it right. The actor Ryan Reynolds — who, remember, owns a soccer team — admits he doesn’t understand it but has sought cover by saying, ‘in fairness, nobody understands the offside rule.’ But now you will understand it. …”
NY Times