>For example, when playing board or card games, I always try and discover some dominant, completely broken strategy that is definitely not in the "spirit" of the game. (...) isn't this how games are supposed to be played?

IMHO, there are 2 necessary criterion on whether or not a game should be played in a certain manner:

1. Is it fun? 2. Will people continue to play with me if play this way?

The first is obvious, don't do things that aren't fun. The second has to do with exhausting the people who might want to play with you - after all, if no one plays with you it's unlikely you'll be able to keep playing the game.

I don't imagine these criterion are complete, however. A dog might want to "play" by chasing a cat, and the cat might continue to "play" if it fears for its life. This is not a thing I allow. There needs to be some criterion for consent, or for the game being "good" for all parties involved.

In the case of card games, I've been very turned off of them before because of broken strategies. I'm not in principle against discovering new strategies that happen to be much stronger than intended ones, but if the game that comes out of that discovery is no longer fun, then I have no incentive to learn how to play the game.