Suddenly you get a sensation that you are in a luxury massage salon. In fact it's down right alarming and could be dangerous. The cause of this sensation is warped brake rotors.
Lets go on.
If the rotors are perfectly flat, your car slows down smoothly. We can avoid collisions with other cars or similar large objects. And we can try to avoid hitting potholes at high speeds. These types of encounters tend to have a deleterious effect on the integrity of a car's brake rotors. Now for the caveats.