Very interesting interview, really sheds some light on the band during this time period. This interview was originally from an issue of Flipside Magazine in 1990. There's a lot of things to take away from it as well.
Biographies give varying accounts of when Green Day started. If you want to be cut and dry, they first took up the name in 1989, but most people also lump in Sweet Children in with that and go back to 1987 when they took that name. But Sweet Children was just another name change as well; this interview shows us that Truant/Blood Rage was really the first Green Day incarnation, circa 1984. I also don't know who that first drummer is, though. They never refer to him by name here; Billie just says "he was kinda weak." And for what it's worth, John also thinks Green Day's an equally dumb name to Sweet Children. Ha.
There's also a lot of coverage here about Green Day's status as a pop punk band (or as the interviewers call it, "pop tart"). A lot of people don't know that Green Day didn't suddenly take up the pop style when Dookie was released; they were playing that kind of music way before. They talk about their views and experiences with heavier genres, and why they stopped playing metal (it's funny to see them still noodling around and playing metal medleys live, though). While Billie didn't consider Green Day talented enough to play hardcore, they sure showed their growth with some of their Insomniac/Nimrod tracks.
Then they go into the songwriting. They'll openly admit, it's pretty much just girl songs at this point, but the conception of 39/Smooth (not yet released at this point), signals a turning point in their career. Billie is broadening their scope, and even other members are contributing ("I Was There"). Though the band goes on to make fun of how many girl songs are still on the album. I still agree with Billie when he says Slappy is where they found their sound.
Also, the topic of sex is brought up, and the band gives their honest response that they don't sing about it; their music is pure. "Dominated Love Slave," "Blood, Sex & Booze," "Fuck Time," etc... My, how the times have changed! Though honestly, I think the band lost some of its innocent nature after Dookie took them to the top. I mean, some of the dark stuff on Insomniac is a day and night contrast to the bright and hopeful songs on 39/Smooth and 1,000 Hours.
And FINALLY, one of the most notable things in there (by a modern standpoint) is the part about politics. Billie Joe just didn't have an interest in it and it wasn't their style. They later talk about how politics in punk rock at this point is a bandwagon thing, and most bands didn't even know what they're singing about. Green Day had a history of going against the grain, and that's ironically what happened by the time 2004 came around. The band's music and songwriting has evolved immensely leading up to that point, but they've always had a different sound.