That's sort of a positive feedback loop, if you find yourself doing well at something then it's easier to stay motivated which makes you work even harder at it.

Personally I spent a lot of time playing FPS games when I was younger but never quite got to the standard for serious tournament play. OTOH I have a friend who got a spot in a well ranked sponsored counterstrike clan after only about 2 months of play.

On the flipside I never put much effort in at school because most it didn't interest me but I still managed to get better grades than many of the kids who worked much harder and had private tutoring etc.