The first colonoscopy I received used fentanyl/midazolam anesthesia which, I learned, has no effect on me. So I was alert and present through the whole procedure and can remember it all clearly. The prep *is* worse. But when they press on your abdomen to get the scope around corners is real bad. And there's a lot of friction when they remove the scope. A lot!
The bronchoscopy I received with the same non-anesthesia was *much* worse.