If you prefer not to delete your Sims, there are a few other "official" and community-favorite ways to keep those bars green:
: Some players use a custom Hacked Coffee Pot that fills all motives instantly when a Sim takes a sip. Why Cheating is Necessary in Sims 1 Sims 1 Cheats Full Needs
: In some versions, you can Shift + Click the mailbox and select "Make Needs Static" to freeze motive decay for the whole household. If you prefer not to delete your Sims,
: Press Ctrl + Shift + C on your keyboard. Enable Move Objects : Type move_objects on and press Enter. Sims 1 Cheats Full Needs
This is the most reliable way to refresh your Sim's mood without any external mods: