Hangman

I actually just realized how easy it would be to cheat at hangman.

It's just one of those games, that you never think about cheating at.

For example: only picking a word at a later stage of the game.

Start by picking multiple words that don't share any letters.

After your friend inevitably loses, just give one of the words that you thought of.

If you want to avoid an awkward situation, just pick a word when your friend still has one or two chances left. You'll have more time to choose a word and it could make for an interesting, albeit manipulated, game.

This ruins the game, so don't do it. Just always make your friend write down their word choice before the game begins.

Alternatively, there's also the method of drawing a stickman with as few lines as possible which is just bad sportsmanship.