Until I was 28 I thought I was an alien abductee, when in fact the memory was of waking up during a surgery on my neck being done with a local and sedation. Personally when it's my turn in thailand I'm gonna ask them to knock me the hell out, then smack me around a bit to be sure.
I've thought about this before, and I can't decide if it would be neat or traumatic. Somewhere out there is a couple videos of the actual procedure. They say you can't feel anything from the injection site down, but having watched those videos countless times I'm not sure I want to hear all the cutting and sucking and digging and the doctor cursing and holding up skin flaps and digging out holes and bloody stuff everywhere. Besides with 5 hours on the table, even if you couldn't feel any pressure or tugging it seems like one would get horribly bored. I guess a sedative inhand with the spinal would be alright, but again it seems like a tramautic thing to wander in and out of consciousness during. Either or I could do, but both sound kinda spooky.
Anyway I believe the only real drawback/side effect is a helluva headache a couple days later, but I guess it's better than 6 months of depression.