What Is A VBT - A VBT (Very Bad Thing) is a thing that, if you do, can corrupt your game and you may have to re-install.
Do not move sims into a house, play them, then move them back to the sim-bin and delete them. It's okay to delete sims you have never played, but the ones you have played must not be deleted. They can, however, be killed.
Do not use the deleteallcharacters cheat, it may leave some parts of character files behind and damage your game.
Do not put an occupied house into the House Bin and then put it back in the neighborhood that it was in. This will corrupt your sims relationships and therefore your sim. And therefore your game.
Do not put an occupied lot into the sim bin and then move to another neighborhood either.
Don't put an occupied lot into the sim bin period.
And don't download an occupied lot either.
Don't add Grim to your family. Or Crumplebutt. Or the therapist.
Don't bartend on owned community lots. It's fixable, but it's annoying dragging out the lot debugger ever five minutes >.< (Met self glitch)
Don't allow Crumplebottom to be bitten and turned by the vampire. Glad I hadn't saved there.
If you're using the Townie Maker and you get a Sim you don't like, don't click "Kill". This is the same thing as deleting a Sim. Just quit without saving instead.
Don't turn off the game or your computer while it's saving!
Do not breed the manequin skintone (unlocked in CAS using boolprop). After the 'baby has been born' notice, your game will crash because the skin-tone isn't availible for babies.
These Very Bad Things may not take effect immediatly, but if you find yourself doing one be sure to back up your game
Yeah, I cant be bothered crediting, but thanks people.
EDit: (Darby)Do not mess with these NPCs at all, except to make babies with them, because that can be done without altering them.
Here's a list of all the "univeral" NPCs:
Toddler New Year
Good Witch Cat