The only time I remember him laughing was when he's lying down among a bunch of knives in a circle. He's the joker, I expected to see him make his sadistic jokes, like in The Dark Knight.
Joker hands a card which is a joker card.
The disappearing pencil trick.
Him having a blast using the rocket launcher.
Etc..
The joker in Suicide Squad looked like he hated doing the things he was doing. He just seemed like a depressed psychopath gangster.