I know exactly what you mean about the on-line idiots playing dodgem cars, and yes it does spoil it.
I used to be shouting my head off at the TV and getting most upset !
My son would be telling me to calm down. " It's only a game dad !!! "
I found that after a while the more 'sensible' drivers invite you to race with them in a sort of closed circle of 'friends', which is much more fun, and testing if they're skilled drivers, which they usually tend to be.
One good thing about the new NFS Shift2 Unleashed game is that it does make it harder for people to push you off or otherwise abuse the game, because any contact normally removes BOTH cars, and it is generally harder to cheat.
Also, you see a lot of 'experienced' drivers moaning about the physics of it, when in fact it is actually more realistic, and they 're having to come to terms with setting their cars up properly, and driving them in a more realistic manner in order to stay on the track and post decent times....which benefits old fogeys like me, who may not have the fastest reactions in the world but can actually drive !