Stevie Wonder: Hell Yeah I Love The Pistons ... I SAW The Bad Boys Play

It's not surprising Stevie Wonder is a Pistons fan ... dude is a Motown LEGEND ... but the reason why he likes the team is another head scratcher from the singer.

Stevie was out at Craig's in L.A. when we asked him if his Detroit roots automatically meant he swore loyalty to the Pistons ... the home team in the motor city.

Check out the clip -- Stevie says he does love the team ... and it's all because he SAW during the Pistons' Bad Boy era of the '80s.