I had one a year ago - the last time I saw my mom alive (last March) in the US, and I fractured my lower left molar on a bone hidden in some pork BBQ I was eating. The tooth was hanging on by a shred of enamel, so (in between visits to see my mom & accompanying her to doctor's appts because she'd fractured her wrist just in time for my visit there!) I rang up my old dentist there in town - who I'd not seen since I was 19 years old (many many years ago

). He took the hanging tooth off, did the root canal & plugged up the hole with temporary white filling stuff until I could get back to England & get my crown done on the NHS. (Fortunately, my travel insurance reimbursed me for most of the root canal expense done in the US.) So yeah - that trip to the US was as much fun as a root canal, plus my mom wasn't in a good state and then some.
I didn't have any infection though. I told him to make sure I was completely numbed up because dentists seriously freak me out, ever since I had all my wisdom teeth removed in one go (which was the last time I saw that particular US dentist!). So he gave me an extra shot - the second shot freaked me out, because it was like I felt a vein in the side of my face sort of 'pop' & I thought - great, I'm going to stroke out here in the dentist's chair a thousand miles away from my home & my husband. I felt light-headed then, but nothing worse happened, although I was still extremely tense & was weeping in the chair more out of fear & frustration (at the whole crappy situation overall) than out of pain. (I didn't ask for gas because I didn't want to pay for it, and I had to be able to drive myself around because I was there alone.)
No pain after the root canal, because they took the nerve out & like I said - there was no infection. Although I made the dentist give me a course of antibiotics just for safety's sake, since I was due to travel internationally again shortly thereafter.
The most annoying part was how long & how many visits it took to get my crown fitted on the NHS. And that cost me a bundle too because I opted for white porcelain instead of the NHS 'special' which is tin & that still costs a fair amount - £100-200 I think? I hate the crown now as well, because everything gets stuck underneath it when I eat - so I'm keeping the dental floss companies in business for the rest of my life now.

It was an international US-UK inter-dental exchange experience!