I've had subtitles turned off since my first SP playthrough, they're annoying af.
Well, I always use subtitles when I have the option. I have difficulty understanding what people are saying often (regardless of language settings), not to mention the sound effects or music often drowning out speech. I wouldn't say that I have particularly bad hearing (or audio comprehension), just that I often find myself needing the subtitles to follow a plot/storyline in games and movies. I feel like people don't enunciate enough, and their speeches end up sounding like turbo mumbles to me.
I can understand subtitles being annoying, too. They take up space on the screen. I've raged at some particularly large subtitles. I've also raged at some particularly badly translated subtitles (SBS in Australia has a lot of French and German movies at night, or used to, and Finnish here), oh man the bad translations, but that's another topic entirely.
TL;DR I envy people being able to not use subtitles.