If I would have strolled into a store and listened to the HD-650 for 30 minutes, I would have walked out without the HD-650s in my hand and probably would have left even earlier. They are now one of my favorite headphones I have heard. To prescribe that everyone should be able to make snap judgments, running through all the different genres and recordings available for a headphone to show its stuff, within 30 minutes, is equally absurd, especially in the case of someone for whom this is their first ever audiophile headphone purchase, as it was for me with the HD-650. I think 2 weeks is a more reasonable length of time. Another great example is the Grado 225s, which I hated for an entire week after running them through my files. I gradually, however, became addicted to their sound signature; I was underwhelmed by my AKG Q701s when I first had them (but was expecting initial disappointment through experience), but once I gave them a chance with certain genres of music, I found they offered a new perspective from which to appreciate my music that did not conflict with that of the Sennheisers; finally, my HE-500s sounded lackluster for the first few days to me, and anyone who knows my posts on other threads realizes my appreciation for these headphones now.
It would be more accurate to say that some people may be capable of making a decision with 30 minutes whether they like a pair of headphones, and if it is an informed decision, it is probably a result of some experience in audio previously, being aware of ones preferences, and even coming in with a variety of recordings to test out. But it is equally viable to remember those people (happy with their Apple earbuds) who did not even give quality headphones a chance, deciding within minutes they sounded the same as every other headphone, as if closing their minds. I do not think anything should be forced on those with such preferences, but I am not going to take their opinion on headphones very seriously at all.