I can't count how many times I was thrown by a kick on the ribs or knocked down with a fierce punch. You need to feel an attack to counter it and stand it in a real situation. It's the only way you're going to learn to fight a real fight.
My instructor said the same thing to me during a public self-defense clinic, which was held two days after I started Tang Soo Do. It teaches so much to understand both sides of it. How it feels, how hard it should be, et cetera.
I would be careful with full contact sparring, in today's world of liability, it's almost screaming "SUE ME!" .