Drifting may seem useless most of the time but it's a real time saver around hairpins.
When going around a turn the best thing to do is have your car grip the ground as well as possible, but, in hairpins gripping can be a major issue due to under steer and can cost you a lot of time and future mistakes because of your racing line, to prevent that i simply go in to a drift letting the car over steer but not spin out giving me a good line, saving speed and saving a lot of precious time!
I will probably make a future post where I explain basics in drifting and slip angle.
Game - Gran turismo 5
Platform - PlayStation3