Why did I have issues scraping off a popcorn ceiling?
What you have is a drywall ceiling that has had popcorn sprayed over it. You can paint over it but you'll have to repair any gouges made from scraping off the popcorn and then prime it.  To remove the popcorn, spray water on it, let it soak in for a few minutes and then scrape it off with a mud knife. The larger the mud knife, the less you'll damage the drywall ceiling.  It's really a messy job so cover the floor up real good.