Overview
Green Day is an American punk and rock band formed in 1987 as Sweet Children. Green Day opened 8 BR shows each on the 1993 Recipe For Hate North American Tour and on the 1994 Stranger Than Fiction European Tour. They are still currently active.
Relationship with Bad Religion
Greg G.: "I don't think they're annoying. I think they made a helluva great album, the first one."
Jay: "(...) they were opening for us on our Recipe For Hate tour (...), and they had just gotten out of the studio making 'Dookie'. They had an advance cassette in their bookmobile and we were listening to it. Brett and I were listening to it and just said, 'This is a fucking great record'. Literally like, 'See you guys later, you're gone', 'cause nobody was making anything close to that. Nobody was making anything that accessible at that time (...). So, it doesn't boggle my mind, they're great song writers, and they're a great, great band."
Green Day asked BR if they wanted to open their tour in summer of 2010. Had they not already booked their tour, BR would have done it.
Dookie Back Cover

The photo on the back of Green Day's Dookie was taken when Green Day was opening for Bad Religion on the 1993 Recipe For Hate tour at the Roseland Ballroom on October 1, 1993. [1]
References