I forgot to mention that I put an intake, exhaust, wheels and springs on my Civic. My engine breaths a little better, the car looks better with the wheels on it, and corners better because of the springs and strut bars, so the mods I did on it weren't pointless. This car was the first thing I've done mods on and I chose to do it as a learning experience.
I think people should modify their cars if it makes them happy, and we shouldn't discourage them since that doesn't help anything.