These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Crowning Moment of Funny: Sonic Youth can be pretty good comedians when they feel like it, but the Are you gonna liberate us girls from white male corporate oppression? line from "Kool Thing" is a pretty strong contender.
The"Ticket To Ride"/"Master-Dik" medley that they played live on air at a radio station and included on the Master-Dik EP: It was apparently an impromptu way to fill up air-time while Thurston was tuning his guitar, and the "Ticket To Ride" portion has him scat-screaming his way through the lyrics to an accompaniment of bass and drums.
When the screaming randomly kicks in on "Mildred Pierce". It's either a Crowning Moment of Funny for some or Nightmare Fuel for others.
Epic Riff: Plenty - "Death Valley '69", "Expressway to Yr. Skull", "Teen Age Riot", "Silver Rocket", "Kool Thing", "Titanium Exposť", "100%", "Youth Against Fascism"... ah, hell, let's just say "all of their songs" and leave it at that.
Genius Bonus: Most of their lyrics make subtle literary allusions that one is prone to miss if one hasn't read the books in question. Sister, in particular, is loaded with references to Philip K Dick. Similarly, "The Sprawl" is inspired by William Gibson's Sprawl Trilogy.
Harsher in Hindsight: "Sleepin' Around", a song seemingly against infidelity that was written and sung by Thurston Moore, can now be seen as ironic in light of Thurston's own infidelity leading to his divorce with Kim Gordon.
Magnum Opus: Daydream Nation. A minority think it's Sister, though.
Nightmare Fuel: Some of their early material, especially "Shaking Hell" and "Death Valley '69".
"I Love Her All The Time" has Mind Rape subtext and sudden freak-outs.
Signature Song: "Kool Thing" is probably the only song the average music listener knows from Sonic Youth.
"Teenage Riot", which they have played on nearly every tour since 1988.
To a lesser extent, "The Burning Spear", a guitar-assault anthem which has been part of their set on-and-off since before their first EP was released.