To present proper evaluated impressions one must listen to it in users environment. Meet impressions generally carry zilch informative or realistic impressions because of a different environment, different demo music, unwanted background noise and very limited headtime. Meet impressions give you an idea but don't treat it as the end be all gathered data/opinion for anything. The HD800's is finicky with amplification most of which can balance the treble, excessive a bit strong to use as it's not much of a boost. Treble is not the only aspect of sound to give the amount of perceived detail. The is also the rabidog(anax) mod that fixes the 6k boost now you're thinking why mod a 1.5k headphone shouldn't it be perfect? Answer is simple as everything headphone has flaws with the 009 extremely close to neutral perfect but at a 3x asking price of a regular HD800. Apart from the treble the HD800's has the least amount of flaws if you look at its objective side, FR, CSD plot and sweeps. But even the most perfect measuring flat 20hz/20khz neutral headphone cannot satisfy every user, we all have our own taste.
That is true, headphones shouldn't be listened to briefly or in a noisy environment. I've never been to a headphone meet and my impressions are from extended use on different days over time in a quiet environment. The problem with the treble being flawed is that the treble is often what causes problems for people such as fatigue, annoyance, ear irritation, etc. on headphones, problems with the treble are sort of a big deal. When a headphone is smooth and linear except in the treble, this makes the treble issues more obvious. I've heard this with many headphones. It all comes down to taste as well, graphs tell you only part of the story, they can be a good reference but not always.