Sometimes the show's greatness lies in the details. This being one of the most famous shows of all time, I don't think I have to spend too much time setting it up.
Right when Birds ends, Trey rips a little chord before putting on the delay loop, which eases into some really sinister space, which keeps building and building. Then Trey turns on this effect that almost sounds like someone electronically yodeling, when then morphs into the yodeling person sounding like they're having a molly-drenched seizure. Riiight when that hits perfect freak out level, only THEN does Fish drop the snare/kick hammer into 2001. It's a tiny, beautiful moment. One that shows how exactly in control Phish were at that point in their career.