My perfect pair of earphones should be on-ear with arms sitting over the ear made of a soft material that does not dig in or irritate behind the ear. The sound quality should be adjustable to take account of either classical or modern music. There should be an in line volume and equaliser control.
I’m quite keen on having some sort of noise reduction to avoid incoming sounds spoiling my listening experience, but also want to know that I’m listening to my music and not sharing it with the rest of the world. It’s not that I’m selfish, but I don’t like listening to other people’s music most of the time anyway, so it’s kinder not to share my own, I guess.
I also like the idea of having bluetooth connectivity, so that I am free of the hassle of cables and wires.
Any chance to personalise the headphones is always an added bonus, I had a pair years ago that had snap-on covers so you could change the look.