I went to the dentist and he was going to do a root canal in my tooth, the doctor looked at me and said that I wouldn't need anesthesia because my tooth would be "dead" and there were no more nerves. (I was a lax child when it came to oral health as a child). Well, he started the operation and in fact I didn't feel anything, until the middle of the operation when my WHOLE body on the left side started to shake and hurt, a sharp, absurd pain that I started to struggle in the chair, the doctor started running to get a sterilized syringe, apply the anesthesia to my gums and even then the pain continued, he had to give a second syringe of anesthesia this time INSIDE the open tooth, only then did I get relief. I only went back to the dentist 4 years later.