I'd have to say most any cans that came with a portable CD Player are absolutely tragic.
But as far as higher end cans that a lot of people actually love, the older pair of Grado SR80's, before they got chunky (thicker) drove me up the wall, even with a decent head amp!
I noticed a gradual shift to a high frequency harshness to them that I just could not bear to listen to anything out of them.
This did occur at the time I got diagnoses with Fibromyalgia and also a very nasty inner ear disorder Meniere's Disease! I am sure it was a complication from my maladies that made my ears more sensitive that brought out this harshness even more. Just one of those things about your Physiology that makes a perfect headphone for everyone almost impossible, that's why I believe picking out a good pair of cans is so personal, as we are all made up of different chemical make-ups.
Now that I have become permanently disabled and deal with Chronic Pain Syndrome, my headphone selection is a very important matter for me, as I use them SO much to drift away in the landscape to not focus on the Chronic Pain.
