I'm curious if it's not so much about anticipation as about association. I think a lot of 1.0 fans especially, associate the songs from the early years with all of their general positive memories of those years, the excitement, the touring, friends, wacky adventures etc. A new song, no matter how good, doesn't connect to those associations because it wasn't part of those memories. So when Tweezer starts you're not just hearing the music, but implicitly remembering all the times you heard it back then and how fun it was. And then newer fans absorb those associations vicariously and come to have a similar reaction.

@travelin_light said:

Tweezer, Simple, and DWD are just better rock songs than Sigma Oasis, Everything's Right, and Wave of Hope. Anybody would rather see the former 3 in a show than the latter, jams or not, and even a non-Phish fan would probably find them more engaging.

Is this true though? It would actually be a good test of some of this stuff. In some cases the older songs might be "better" than the newer (to the extent that kind of language makes sense when talking about art, music, creativity, etc.), but I doubt it's true in all cases.

Tweezer, for example -- if it never existed in the 90's, and was just debuted by Phish this year, what would you really think of it as a song? While the signature riff is catchy, there's not all that much going on musically. I actually find the song itself a little grating. But I love Tweezer, because I associate it with epic jams and because it has such a storied history and because it brings an explosion of positive energy from thousands of people all at once.

I could be wrong. And for sure songs like YEM, Divided Sky, Foam etc. represent compositional achievements that Trey largely isn't attempting anymore (and when he does, people are weirdly hostile *cough* TTE *cough*). But I suspect that at least some of the "old songs are better" bias is actually just people's brains saying "I miss the experience of being a Phish fan in the 90's" or "I wish I had gotten to be a Phish fan in the 90's".