There are so many factors in Motor Racing - Circuit (and they're all different, even the U.S. ovals), weather conditions, how the cars are set up, driver skill / experience / bravery, development, team, car, tyres, tactics, rivalry, etc.
And then there are so many strands of motorsport - Formula 1, Touring Cars, Sports Cars, Classics, Single Seat smaller formulas, One Make saloons, Rallycross, Rallying, Motorbikes, Sidecars, Trucks, Bangers, Dragsters, to name a few.
I don't think I've ever watched a truly boring British Touring Car Championship race. If you go and watch them at the circuit (as I sometimes do), there's so much to see and do there.
But it's a case of each to their own. I'm not going to critisize football though, as I like that as well. But Motor Racing will always be my main sporting interest.