Chumlee is often the butt of everyone's jokes on Pawn Stars, which actually makes him quite sympathetic. Yes, he’s not the brightest in the bunch, but that makes him lovable, like a teddy bear that you want to hug and pat on the head.
Pawn store employees should be tough and know how to play hardball in order to cheat the customer out of the most money, but Chum isn’t like that. He, instead, often tries to give them the best deal possible because he’s a great humanitarian and actually cares about them. If Pawn Stars had a heart, it’d be this guy.
Also, he’s clearly got the emotional maturity of a 10-year-old and often gets excited about fun purchases the store makes. How is that not endearing?