Well I'm quite hard of hearing, wearing hearing aids, and what gets my goat most of all is the awful sound quality on some otherwise gripping dramas. There's mumbling and muttering, quite often exacerbated by "dramatic" background music. I've abandoned more then one drama series in my time over this. I've also had to abandon a couple of phone calls to utilities because of exceptionally rich regional accents, one from a Geordie and one from someone in the subcontinent. I suppose the Beeb et al. do have tricky decisions to make at times as to whether to use subtitles.