TestingCheatsEnabled True
Do not forget the space in between Enabled and True. This will mess up the whole cheat. Anyway, type in the cheat, then hold shift, and press the mailbox. This will give you an advantage on picking jobs, re-boosting your sim's mood, and even making you be friends with everyone in town. This also involves some things like making your need "Static" (This means that they will never change. There is another option called Make Needs Dynamic, which makes your needs gradually drop as normal.)