I've never had a root thing, I've only had teeth pulled.
How bad are those root things?
Root canals are supposedly not as bad as people say, but most people consider them to be the last resort of dental work. I think a root canal is the worst thing that can be done to an individual tooth.
The reason why it sucks so badly is the procedure. From what I know, they drill a small hole into your tooth, stick a small tube in it, suck out the nerve, clean the empty space, then fill it with a kind of cement. There's a lot of scraping, cleaning, suction, and drilling. It's extremely uncomfortable, especially because it can take some time. During some parts, you might experience sharp pain from the nerve exposure or scraping when they clean out the nerve in your root. The whole time you're drooling all over yourself, with a suction tube in your mouth to remove the drool and small shards of tooth that were drilled, all the while smelling and tasting the smoke from the drill and rubber from the gloves and tubes. It really does suck, but it's more uncomfortable than painful. Once you survive it, you feel pretty darn brave. B) ...Kind of.
And there's more, since I have to have crowns placed over that. But, uh, I think that's enough detail. ._.
I think I had a rare awful experience last time because it was an infection. Once they put in the cement, the pain goes away (probably because it protects the inside of the tooth from being exposed to air and temperatures). They weren't allowed to put cement in there for a week or so, because I had to be on antibiotics (the one kind I haven't had an allergic reaction to yet). They had to go back and make sure the infection was 100% gone before closing it up.