Personally don't like artificial noises in the cabin - but as has been pointed out intake and exhaust systems are tuned to make them sound "nice". Worst still, in my book, are sports exhaust systems which ape faulty carburation of the past and pour petrol down the exhaust where it pops and bangs as it hits the hot manifold.
those pops and bangs can do1 as far as im concerned.
a decent exhaust that gets the gas out as fast as possible with a decent map makes the car sound amazing. i love how mine sounds.