Do headphones requiere break-in?

My HD650 and AKG 702 sounded great from the first day til this day. My Grado SR60 sounded bad from the first day until this day. They are not very good. And they are uncomfortable also. Another high-end legend. Same category as the Sony 5400 entry level Vandys and the Oppo stuff. Does not mean they are all bad, just over hyped. Anointed 'Giant Killers'.

"I didn't have the gumption to ask him to explain the whys and wherefors, just thought he knows what he's talking about.
'

What a wasted oppourtunity. One of THEM actually stepped down from Mt Olympus to speak with us mortals, and you froze!!! How could you not have asked him!