Language, history and curiosities in games.
I recognise good playtesters by my (frequent) urge to strangle them.
You see, designing games is magic and your creation makes you feel so happy and fulfilled. This feeling crumbles when you have to face the playtesters who are realistic and find the weaknesses of a game.
My advice for new designers is to take more time playtesting a game than designing a game.
If the game has not been played without the designer present, it has not been playtested.
There’s nothing quite like a physical playtest of your ideas.