Lives. Yes, lives. Especially in newer games. The "lives" system was created as a way to let the players have a couple of tries for a coin way back in the arcades. Then in the console it was a way to artificially create difficulty and add length to a game. Nowadays, I don't need more tries in exchange if a coin, neither do the developers need to artificially create length. If your game is so basic you need lives nowadays, find another way to increase the challenge.