I've gone under a Anesthesia a few times. That is, ofcourse aside from the dentist office when working on teeth. The few times I had general anesthesia, and not a local area, like the mouth, I had a few surgeries that required removing something that couldn't be done while awake. Had 2 bone spur removals and all of my wisdom teeth pulled at once. The wisdom teeth I had to be completely under, due to how deep the roots went, which the top two had roots going up into the back of my nose.
I've had different kinds depending on what procedure needed to be done, dental, mole removal, surgeries, and I even get a spray type to numb my nose when I have my scopes done to check for cancer recurrence. Sometimes the heavier doses can make me sick to my stomach and especially after surgery.
Been though it once and it wasn't bad as I thought it was then again when they insert it into you then about 2mins later you are gone. Anesthesia something you wake up from afterwards and you feel like only 5mins has passed but in fact it was 4 hours
I've had local many times (for example, last month I got a steroid shot in my knee, so they anesthetized my skin near there.)
In terms of general, I've only had that once. It was during a minor surgical procedure known as an ablation, used to fix my heart problem- basically, my heart had way more electrical pathways than it needed, so they put me under while they burnt the extras away. Sadly didn't get any local or regional while they needed me awake to find the bad nerves by making me convulse on the table. XD
I did when had my wisdom teeth out in hospital. The woman couldn't get my vein, my hand was black all over from that bruise. I also had Tachycardia when then tried to bring me round, I could hear the docs panicking (wrong word I can't think of it) and saw something, which people laugh at.