The unique and worst part was the on-and-off air-bloating pain, but it was comparable to other quickly-passing episodes of intestinal gas/discomfort, and especially bearable knowing that it was very temporary and in service of a goal under expert care. (I've had more painful headaches, scrapes, stubbed-toes, and sprains – which each lasted longer.)

I could definitely understand those with various kinds of medical- and pain-anxiety opting for sedation, but I also think such things are highly suggestible and influenced by social norms about which pains are normal to shrug off and which pains you communicate for sympathy... so it doesn't surprise me that in other cultures skipping sedation could be the casually-accepted norm.