A passed pawn can't be stopped by pawns so it's the one most likely to queen. You can't queen a passed pawn if you never push it. It all depends on calculation of course. Like all simple chess rules it's usually true but not always. If you can queen it push that pawn. If your opponent can take it then you have to wait… www.quora.com
In my current online 4-player tourney several games have been dominated by passed pawns which have put pressure on the opponent.