Artist Disillusionment: Rivers Cuomo has shown it in several interviews, and it's essentially the theme behind "Across the Sea" on Pinkerton (in the guise of a reply to a fan letter from Japan). When applying to a course in Harvard he wrote this about his experiences on tour:
Fans ask me all the time what it is like to be a rock star. I can tell that they are dreaming, as I dreamed, when I was a kid, of someday ruling the world with a rock band. I tell them the same thing I would tell any young rock-star-to-be [...] you will get lonely. You will meet two-hundred people every night, but each conversation will generally last approximately thirty seconds, and consist of you trying to convince that no, you do not want their underwear. Then you will be alone again, in your motel room. Or you will be on your bus, in your little space, trying to kill the nine hours it takes to get to the next city, whichever city it is. This is the life of a rock star.
Ascended Fanon: The lyrics (specifically the "moaning" part) of Perfect Situation were changed after the band noticed that fans enjoyed singing the third moan in a more upbeat fashion.
The cover of Hurley is a close up of actor Jorge Garcia because Rivers said he just felt happy when he looked at it.
Creator Backlash: Due to the initial poor reception, the band all but threw Pinkerton into Canon Discontinuity for years, until it seemed that Rivers Cuomo was the only person left who disliked the album. He mellowed out lately, even playing Pinkerton in its entirety.
Executive Meddling: "Beverly Hills" started as a fairly straight and optimistic song about how the singer genuinely wishes he could join that society but got mutated into something much more bitter and sarcastic-sounding.
The band wanted to produce Blue themselves, but Geffen pushed them to get an outside producer, so they settled for Ric Ocasek. When Green came around the label also said no since their self-produced Pinkerton had tanked commercially and critically, so they once again brought in Ocasek.
The band initially wanted to use a collage of sampled dialogue for "Undone - The Sweater Song" playing on the theme of contrasting extremely optimistic and extremely depressed dialogue. Geffen nixed the idea at the last minute since they weren't eager to go through a long sample clearance process, and as a replacement Matt and the band's friends Karl Koch and Mykel Allan recorded the now-famous spoken-word dialogue. Geffen's rejection came after the sessions for the album were finished, so the dialogue was recorded in Los Angeles and had to be flown to New York to be added in during mixing.
Rachel Haden of that dog. sings on "The Good Life"'s B-side "I Just Threw Out The Love of My Dreams", one of the few Black Hole tracks to be completed before the album was abandoned. To this day, Haden is the only non-Weezer member to do lead vocals on a Weezer song (unless you count Lil Wayne's A Wild Rapper Appears verse on "Can't Stop Partying").
One of Us: The guys of Weezer are geeks. Rivers Cuomo is actually a Sailor Moon fan, as evidenced by two of his guitars.
Rivers is also a big soccer fan and wrote "Represent" as an unofficial anthem for the U.S. national team for the 2010 World Cup. He also wrote "My Day Is Coming" (released on Alone II) for the 2006 World Cup, initially intending it to be a triumphant song but some bad results caused the song to become downbeat instead.
The Pete Best: Jason Cropper, who left/was kicked out of the band (depends on who you ask) during the Blue Album sessions because his girlfriend became pregnant, forcing Rivers to record all the guitars. He only earned one writing credit, for creating the acoustic intro of "My Name Is Jonas".
What Could Have Been: Most well-known among fans is Songs From The Black Hole, their abandoned Rock Opera. Rivers Cuomo went as far as recording a home demo version of the whole album, but it was scrapped in favor of what would become Pinkerton. Rivers claims the idea was abandoned due to a combination of his increasing doubts about the concept as well as Matt Sharp putting out The Return of the Rentals (an album heavily indebted to the Black Hole demos), which made him anxious to not be perceived as "stealing" from his bandmate. Most of the songs were either slightly adapted for Pinkerton, made B-sides or released in the Alone demo compilations.
Rivers had also planned to have the character Maria be voiced by Joan Wasser of The Dambuilders, but he neglected to ever mention this to Wasser.
Rivers had prepared an entire new batch of demos for the follow-up to Maladroit before abandoning them entirely. An essay he wrote later admitted that he was undergoing another Creator Breakdown over the fan backlash towards Green and Maladroit and his own behaviour towards them, and credited Rick Rubin with helping him by introducing him to meditation.
The band almost made HurleyanotherSelf-Titled Album, but gave up on the plan when they realised fans would just call it "the Hurley album" anyway.
Word of Saint Paul: Karl Koch is considered such an authority on Weezer (especially because he's known them for a year before they actually formed) that whenever Word of God is unavailable, fans usually ask him instead. This happens so often fans Punnily refer to the practice as Karlification.