I realised that life is just like playing volleyball.
People get numb when they encounter the same things over and over again. It's like when you first got hurt by someone, you really feel the pain and everything. But when you experience it again, you don't feel as bad as before. And it continues. The more you experience it, the more numb you'll feel.

It's the same as volleyball. When you first started playing, your hand gets very red and painful. And it hurts even more when the ball hits your hand again and again and again. But you will reach one point whereby the pain isn't that bad and your hand is numb, numb from the pain.

I came to this conclusion when I was playing volleyball with my wall, and realise it's kinda true.