I was offered anesthesia for the endoscopy as well and I was glad I refused. The whole thing was over in 10 minutes, the actual endoscopy was about 2 minutes of serious discomfort. I gagged a couple time, the rest of the time I held steady, but the nurses also complimented me for powering through so I don't think it's expected to be easy. It was a weird and humbling experience.

If you feel like you're relaxed enough to be calm when someone does something to you that your body will tell you is going to kill you, then it's not so bad. They sedate your throat to kill the gag reflex, but it doesn't work 100%.

The upside for me was that it was over so quickly, and I could go on with my day, was allowed to drive, etc.