So, I'm trying to make a clean game with no default neighborhoods. Ater deleting the neighborhoods (from documents) except Tutorial, it finally has no neighborhoods. Though then, checking around I found this
http://simswiki.info/wiki.php?title...g_Neighborhoods
It says I should not delete neighborhoods by simply deleting the folders, I'm not sure if it's referring to the ones I deleted or the ones in the packs.
I've also made some custom neighborhoods to look into the terrains I've downloaded from people, and if I didn't like I delete the neighborhood.
Will these ruin my game?

That article was written in 2007 and is probably based on erroneous information.
It's fine to remove neighbourhood folders from your userdata by deleting them.

There was some mystery about the neighbourhoodmanager file and I think the consensus used to be that removing neighbourhood folders would somehow mess that file up. We now know this to be incorrect- what this file contains is detailed here:
http://www.modthesims.info/showthre...671#post5517671

I don't think there should be any problems. If there are any, try deleting the NeighborhoodManager.package. It will regenerate and any wonkiness in the main menu should go away.

What you're truly not supposed to do is delete subhoods outside of the game, as those are integrated with the neighborhood and there's no easy way to delete just those alone via Finder/Explorer.