So far it appears that PET has yet to develop a sense of humor about himself except for his hair. Think he'll loosen up a bit?

He tweeted about SNL and it was not a compliment. Hillary was mercilessly mimicked on SNL and she laughed about it. She even showed up as a guest on the show. Why can't PET laugh at himself? Why is he humorless in general and very serious/somber/sober in specific about himself? Everyone should be able to laugh at himself/herself.  Right?