When he was a baby, I longed to hear him laugh. He didn't. He wasn't a laugher. He laughs now. But mostly at slapstick. He laughs when someone else gets hurt. He laughs when we punch him. No seriously, the boy begs to be hit. He loves rough-housing. I avoid it as much as I can, 'cause it creeps me out. But he never laughs so loud or so gaily as when things have got out of hand. The only time I've ever heard him genuinely laugh at tv was at Tom and Jerry.
He sometimes laugh when we laugh. But it's a forced laugh. Ha, ha, ha. A laugh akin to the praising of the fine hues in a painting by the color blind.
He's missing some teeth, too. They just never came in. But that can be fixed with money. A lack of a rich, complex sense of humor can't.
I'm hoping that as his language skills become more sophisticated his sense of humor will develop, too. But I'm lowering my expectations.