Okay, so I'm not going to tell you what ppl post ALL THE TIME (its the same thing, and it gets annoying), and I am not going to tell what types of emotions are appropriate or each mood, (look on another post) so listen up. But in case you DON'T know, the basics are:

sad- sim looks down, depressing music plays

angry- sim has hands on thier hips and glares a you, angry music plays

content- not fully happy yet, smiles, (gets sad when you laugh, FYI), normal music plays

Happy- sim is grinning, bar goes REALLY high when you laugh, joyful music plays.

Okay, so you have the basics now. Here is a cool hint: when the sim is in 'content' mode, use encourage, and a music note comes from the sim, and then the sim gets happy. NOW you can laugh on the game.