Right up to version 2007, there was a really dangerous button labeled “Delete Special”. It seems harmless enough, but in the wrong hands it could be lethal.
If you don’t already know, when you select a collection and click “Delete Special” it would actually delete all the computer objects that were a member of that collection from the database, but not delete the collection itself. Seems like a handy thing, but not when people click it by accident when they meant to delete the collection object.
ConfigMgr 2012 SP1 doesn’t have a delete special button anymore. The feature is still there, but it works a little bit differently.