The first one I had done was about 9 years ago and I cried like a baby (nearly).
I'd never had so much pain in all my life everytime he jabbed the metal into my tooth to take out the nerve.
It got to the point where he couldn't give me any more jabs and I had to endure the pain.
My mother actually took me (I was 40) and when I saw her I just put my head on her shoulder.
I then had to have another 2 or 3 visits to finish off and there was bad pain on every visit.
A few months later I had to have another one done and I considered being put asleep but it would cost another £70 on top of the £230 for the root canal.
I decided against it, tensed myself for excrutiating pain but none came.
he dug and dug and I felt nothing.
I asked why and he said that the first one was a live root and this one was a dead root.
About a year later I had a bad abcess and the pain was really bad.
Again I opted to save the tooth but he said I couldn't have an injection because of the abcess so he would drill + dig without anaesthetic

He told me the pain in my abcess was so bad that when he drilled in I'd feel instant relief - yeah OK.
He was right and I had a root canal without a jab.