Is it normal that i like the smell of gasoline and exhaust?

I agree on the gasoline part, but not the exhaust... Exhaust smells terrible, especially in new cars that burn fuel efficiently.

Most car fluids smell nice. Fuel, coolant, oil, brake fluid, power steering fluid. All have their own scent and none of those smells are bad. Before I got the ignition timing right on my project/ weekend 1984 BMW 635CSI, I'd turn my whole garage into a gasoline aroma therapy session XD
A well tuned and maintained engine also smells nice. I can't describe it, but after the car has run for some time, you park up and open the hood, there is a slight engine smell you can't quite define, but it's there and it's nice.

This smell is only present on well maintained cars that are 7+ years old. New car engines don't smell. Badly maintained engines have a very sharp and unpleasant smell.

... what about farts?

It's not the worst think you could smell and like but I don't think it is healthy.