That depends on whether the tooth is "impacted" or not. That is, whether it's below the gum line and still deeply imbedded in your jaw, or whether it's already pushed through the gumline and is an independent tooth. If it's impacted, they'll probably use a very quick-acting, mild, general anesthetic and you'll simply wake up with very mild pain and it will be over. If it's not impacted, they'll use local anesthetic, pull the tooth, it will be over in minutes, and you'll feel nothing but a bit of pressure. Either way, there's nothing to be terrified about, because the only pain is later when the anesthesia wears off, and it's really not that bad. Kinda like a sore tooth, nothing more.