What Are "Vocal Jams"?
You Enjoy Myself (aka YEM) typically ends in a "vocal jam", an extension of the Hey! exercises in which the instrument-playing stops but the music continues, through a free-form offshoot of skat. Some classic vocal jams include 8/9/93 (with lots of teases, then a brilliant transition into Contact), 11/14?/94 (Cat's Cradle, with a crazy chicken/cheeseburger rant), 9/29/95 (which erupted into a fabulous "clicking" rant), 4/26/96 (in which they started the opening lyrics to the next tune, Wolfman's Brother), 12/6/96 (with Mike solo and "Everybody go nuts, I like donuts!" chant), 10-31-95 ("Fuck you up the ass"), 8/12/98 ("Who's your daddy? / Oooh Chicago"), 1/3/03 ("George Takei", best known for his role as Hikaru Sulu in StarTrek).
Chris P. Thorn suggested (9/1/98) a possible influence from Pink Floyd's Ummagumma: "I couldn't help noticing a close kin-ship between 'Several Small Species of Furry Animals...' (a synthesized sound effects track by Roger Waters) and the vocal Jam on You Enjoy Myself. Is that where it comes from, or is it just a coincidence?"
To note, Trey has said (New York Post, 1/1/99) that YEM "sums up our first five years".
Also, "during the 2-21-97 YEM *in* Firenze (Florence), the crowd goes nuts every time they sing WUDMTF, and Trey or Fish says, "This is a dream come true!" The crowd is also clearly singing along to those most unintelligible of Phish lyrics.
The band Yes has a song called Fish which sounds at least something like YEM.