Similar story here:

I was 14 years old and playing cards with my everyday-to-church grandfather. I did a move, he called me a gay fagot for it.

Didn't think twice: threw the cards in his face and told him to go f*ck himself.

It wasn't him calling my move, it was him using those nasty words that triggered the anger.

The good thing: from that day one, he understood that times had changed and didn't use those words anymore.