I was afraid that I would find being spider-gagged and tied up naked and wearing a tit-press and a spreader bar enjoyable. And I was right to be!" Image source: WhippedAss.com.
I came across an interesting bit in a blog for a tantric teacher of some sort. He was doing a mild 50 Shades of Grey style bondage demonstration at something called "Sexpo" which required some female volunteers. He said:
As part of the preparation for the experience I asked all of them what scared them most about it. They all said the same thing. They were scared they were going to enjoy it.
It's an interesting insight, which unfortunately was followed up with a bunch of New Agey blather that reminded me strongly of bad kajira poetry. (No, I won't cite any examples because that would be wrong, but if you google "kajira poetry" or "kajira poem" you'll find plenty of examples.)
A lot of people are afraid of pleasure. Perhaps that's what motivates prudes to advocate censorship -- terrified people standing on the shores of a lake, pointing at the happy swimmers cavorting in it and declaring that swimming is a sinful, terrible thing.