When someone dies, why do some people act like they were much closer to them than they really were?

I don’t get it. Also, a person can have been the biggest AH in life, but after he dies some people carry on like he was the greatest guy in the world. So witty, and funny, and smart, and charming…even if he was a slobbering, lazy drunk who beat on his wife and kids.

Why do people do that?