I think Katarina is the most anti-fun champion. Her kit is designed around sweeping teams instantly. An 0-10 Kat can still get a pentakill with timing and luck, and her kit takes all of the fun out of a game.
When she's running directly at you, she'll throw her dagger and shunpo behind you. Prepare any stuns you may have accordingly, she's going to use her abilities/ult right there.
When you sense she's looking to play, typically by when she's running directly at you, is to simply auto-attack onto her. If she uses Shunpo she will then be placed on the direct opposite side of you, except for when your back is against a wall/tower/minions.
