They discussed heart-wrenching ballads like "Enough for You" and "1 Step Forward, 3 Steps Back," the somewhat surprising album opener, "Brutal," and more.
Below, see a few highlights from the nearly 22-minute heart-to-heart about the songs of Sour.
'Brutal' Is the Opening Number, But It Was a Last-Minute Addition
"I actually wrote 'Brutal' like two weeks before we had to turn the record in, which is very late in the game," admitted Rodrigo. "It's one of my favorite songs on the record. I think it sounds really unique, and I love the songwriting of it -- I think it really represents my teenage years very well. I really wanted to put it as the opening track. Everyone was like, 'Olivia, are you sure you want to that? It's kind of weird,' and I was like, 'Love it. I wanna do it.'"
She went on to explain to Sang what exactly an "ego crush" (from the song's lyrics) is: "An ego crush is just like feeling like you're so inadequate and inferior and getting angry about it ... feeling like your entire is just like, gone, which I think is something that I definitely felt and something that teenagers feel, I suppose, as they're growing up."
Moreover, she said, "It's a song about when you're in that pity party and you're just like feeling sorry for yourself -- it's stuff that you would say when you're in that."
"It's sort of funny to have songs get big about like, how much you feel like nobody likes you," noted Rodrigo. "It's sort of ironic and weird."
How Taylor Swift (And Those Birds) Ended Up on '1 Step Forward, 3 Steps Back'
Chirping birds can be heard in the beginning of "1 Step Forward, 3 Steps Back," an idea that Rodrigo's Sour producer, Daniel Nigro, came up with -- and she loved it.
"My producer Dan, he actually just like stuck a microphone out of his window of his house and recorded the birds in the morning and put them in the song, which I think is great and it sort of adds a cool ambiance," Rodrigo said of the track that was overall inspired by a text message.
"I really sort of loved that concept of '1 step forward, 3 steps back.' Somebody texted it to me once, and I was like, 'Ooo, that's really interesting. I've never heard somebody say something like that.' I thought it would be a cool way to describe this toxic, sort of manipulative, relationship."
Swifties will immediately recognize the piano from "New Year's Day" on this tune. Rodrigo offered some details about how that came to be: "We interpolated 'New Year's Day,' which is Taylor's song from Reputation. I came up with the '1 step forward' concept and I sort of wrote a verse and a chorus, and when I got home -- I was in the car on a road trip, and when I got home, I decided to sing it over the chords of 'New Year's Day.' I think they're really beautiful chords. I was lucky enough to get that approved, and it's on the record now."
Don't Assume That 'Enough for You' Is About a Romantic Relationship
"'Enough for You' is one of my favorite songs on the record," Rodrigo revealed.
"I wrote that entirely by myself which I'm really proud of. It's super, obviously, very insecure and vulnerable, but I also love how it's really hopeful," she said, referencing the turnaround point of the song, when she comes to the realization that "someday I'll be everything to somebody else."
"I don't think it neccessarily has to relate to a romantic relationship. I think I feel inadequate in many sort of relationships, whether that be a work relationship or a friendship relationship," said Rodrigo.
Why 'Hope Ur OK' Was Rodrigo's Ideal Closing Track
"'Hope Ur OK' makes me really sad, in a great way -- it just makes me really emotional. It's a super personal song about people that I really love. That one gets me," Rodrigo said of Sour's sweet final note.
She continued: "I feel like it's super hopeful. Sour is a very sort of sad, angry, emotional record, and I wanted to end it with a song that was like, you know, 'We're all gonna be all right. We're gonna get over it. Everything's gonna be OK, and we have each other.' It was really important for me to end this sort of somber record on that note."
Watch Rodrigo's full conversation on the Zach Sang Show below.