The absolutely epic guitar at the end of "The Worst Guys".
The bridge of "Sober" (after Bino says "yeah" and cuts off the chorus). Everything from the pitch-shifted vocal bits to the grainy distortion heard throughout, and the guitar. Especially the guitar.
As if that wasn't awesome enough, the video couples the bridge with some Crazy Awesome dancing from Bino.
Bino's screaming in "Me and Your Mama" is enough to send chills down your spine. Like the song or not, you have to admit that he's got quite the larynx.
"Redbone" in general, but mainly the fact that many speculated that Gambino's voice was pitched up in the song only for him to reveal that that was 100% his all-natural voice with no additional effects.