What he said stayed with me, because I have the same problem.
What I have noticed is that smart people with a sense of humor always like me. Not-very-smart people with no sense of humor tend to not like me, to the point they tell lies about me and try to do things to hurt me.
I always give people the benefit of the doubt. I'll change my mind. Some people, unfortunately, are so dumb they cannot change their minds. They always think they're right.
Some people have something wrong with the way they perceive things. Our perception goes though our emotional brain first, so everything we perceive is always colored by our feelings. If a person is childish - and God knows many are - what they think about someone is always affected then they'll never be able to judge people correctly.
There are not very many smart people with a sense of humor, who try to be fair. There are many dumb people with no sense of humor at all. That's a shame, of course.
Of course, I always keep the smart funny ones as friends and avoid the dumb ones.
Another thing I've noticed is that dogs are excellent judges of character, far better than humans, and they immediately perceive the dumb ones with no sense of humor, who tend to not like dogs.
I once was sitting in my van with my pug, who are the clowns of the dog world, and are funny and affectionate. Some guy walked up to my door and asked for a cigarette.
My pug hurled himself snarling across my lap and tried to attack him though my window. I told him my dog did not like him and to go away and never bother me again.
Later I mentioned this to a woman, who said her dog hated him and that she referred to him as "Grumpy." He was stupid, had no sense of humor, and harassed everyone to extent he ended up serving 20 days in jail and got thrown out of his apartment.
Her dog, on the other hand, when she saw me, wagged her tail so hard she could barely walk.
I've also found a lot of middle-aged women who marriages failed also dislike me and try to do things to me. But then, I'm not alone in that. These women are full of bitterness and anger, and they try to do things to other men.
Smart people have it harder, dealing with the stupid. God knows how Bill Gates had it growing up, since he looks like the archetyical nerd. Of course, now, with his money, he can completely avoid the retards.
I wonder how many problems in the world are caused by stupid humorless people who don't like dogs? A lot, I'd say.
Look at this way: when was the last time you met a smart bully?