Enable the move_objects on code when your Sim is sleeping. Enter buy mode and remove the bed on which the Sim is sleeping. The Sim will disappear. When you return to live mode the Sim will reappear somewhere else in the house and all mood bars will be at 100%.
If your Sim is very depressed, enable the move_objects_on code and pause game play. Click on the Sim in buy/sell mode and click the bottom of the screen to delete him/her. Once deleted go to the live mode and double clock the person's head icon to go to where that Sim is located. Everything should be close to full. Note: Wave the game immediately before performing this cheat, or you will lose any career changes or points you have earned. When done to a child, their report card goes to a B-.
Enable the move_objects on code, then select a walking Sim with a bad mood in the buy mode. Then, "sell" the Sim. Go back to the live mode and click on the icon of that Sim. Check his/her mood and all except "Room" and "Fun" will be full.
Enable the move_objects on code. Have your Sim to take a shower of bath. When he or she is in the shower or tub, pause game play and enter buy mode. Click on the shower or tub and delete it. Your Sim and tub/shower will be gone. Your tub/shower will be gone permanently, but your Sim will be walking around in your house somewhere else, usually their room. Their "Energy", "Happiness", and sometimes "Fun" will be almost full.
If you are having extreme trouble keeping a Sim happy, usually when you cannot get their social or room rating up and you are low on money, save your game. Evict the family, then move them back into the same house. Now you can start over with a clean slate.
Sit your Sim on a couch and enable the move_objects on code. Go to build mode and delete the couch when your Sim is still on it. Return to live mode and time will go into fast forward as if you were sleeping (if there are no other Sims currently in the family). Then, click on the Sim's face at the bottom of the screen and everything but your bladder will go up all the way. Note: At times one skill point for body may be lost. This may also cause your Sim to lose job skills.
If your Sim is very unhappy, save the game and exit to the neighborhood screen. Click "Evict", and evict them. Then, move them into the house you want (either the same one or different) and furnish it. Your Sim will now be very happy. Let him or her go to work like that and get a promotion. It helps you do better in school or work, and makes them happy.
Use the following trick for all green bars except for Bladder. Note: This will only work in Play The Sims mode. When your family is in a bad mood. go to the "Start" menu then select "Save". Then, go to the neighborhood and select "Exit Neighborhood". Press "Evict" then move them back in. They should now be in a great mood.