Digg Nitrous! Great buzz~~~~~happy and not stupid, not so much anyway.
Nitrous, aka the Truth Serum, aka Laughing Gas. My dentists no longer offer it.

Not only do you have to be skilled enough to get the right mix of gas and oxygen, but it attracts burglars.
I am sure I could have gotten through my last root canal without it just fine, but I was inhaling the stuff as fast as I can go. While in the middle of cleaning out my tooth, the dentist was talking with his staff about his basement flooding. For some reason, I got the giggles. Giggles in the middle of a root canal!
That same endodontist had one lady on staff, whose sole purpose (at least while I saw her) was to hold your hand while the novocain was injected and during the procedure. That was really cool. Unfortunately, they no longer practice here