Grinding is only boring and repetitive if you just try to be average while doing it allowing for a huge margin of error.  Compare this to playing chess or poker, is it "grinding" there to play the same thing over thousands of times?  If you are just mindlessly shoving pieces around a board, going "all in" every hand without looking at your cards, or if you just randomly "grind" -- yes all 3 of those activities sound horribly boring to me.