I share the opinion, but I know why. It's because they're boring, and I'm not able to put myself into the story in the same way as other writers. Most "smut" isn't particularly well written, and tends to only work if it's your type of sex.

A lot of books have sex scenes in them, and most feel pointless if they don't advance the story or characters in any way, and tend to be all physical actions or emotional descriptions.

Few sex scenes have been done well, though I enjoyed Joe Abercrombie's sex scenes for how they were written. Red Country has a fantastic scene involving getting drunk, having sex, and then the hangover. The prose slowly breaks down into poorly punctuated verbal streams to give a near perfect written "drunk" feeling, then turns into all sharp short, painful punctuation for the hangover.

I strongly disliked the erotica in the Grey Bastards series though, it felt like it came out of nowhere and offered nothing I wanted to read. I especially didn't want a half orc gang leader to be taught how to squirt by a gigolo slave boy.

Some people like that kind of thing though.