Creator Backlash: Anthony doesn't like "The Greeting Song" very much - it only exists because Rick Rubin told him to write a song about girls and cars.
Anthony has also complained about "Knock Me Down" and refuses to do it live, complains about the "One Hot Minute" period despite fan desire to hear the tracks, and basically regrets his personality in the 80s even though he was really cool.
Doing It for the Art: John Frusciante's attitude for a long time was to stay out of the spotlight and just play music, and avoid anything that could be construed as "selling out"; he left the band at one point over it.
The reason he ended up leaving the band was that his heroin addiction was affecting his will to perform live. The whole "selling out" thing was partly true, but was ultimately a more palatable story to tell the media. Another part that the media rarely hears is that Anthony was bullying him, which made him feel too much like being in the band was a job. This is part of the reason why John was given so much creative control in the Californication period onwards - Anthony felt guilty about the way he'd acted.
Dye Hard: Anthony dyed his hair blonde during the Californication era (like in the picture above). Went back to the usual color by the time By the Way came out.
Not quite. During the By The Way period his hair was actually dyed black. Usually, it's a medium to light brown.
Flea has constantly been known for dying his hair various colors, most frequently pink and blue. He is doing it more often because his natural hair color has faded over the years.
Chad Smith bleached his hair in the "One Hot Minute" period, as can be seen in the back page of the album's booklet and some posters for the period. Before that he had long black hair. For the Californication period onwards he shaved it off and wore a hat or bandana, and has remained that way since.
Promoted Fanboy: John Frusciante was a devoted follower of the band's early early career, before becoming their guitarist in 1988.
Now this has happened twice with Josh Klinghoffer, although he was a long time friend of the band by this point (having already recorded with John Frusciante and toured with the band). The band knew Josh since 1997, when he joined their mutual friend Bob Forrest's band "The Bicycle Thief". The bands toured together in 2000, and Josh became great friends with John Frusciante, recording several albums together, both as part of John's solo work and as Ataxia. Klinghoffer toured with RHCP as an additional guitarist on their Stadium Arcadium tour in 2006-2007. The band took a year's hiatus, after which John Frusciante left, and Josh stepped in to fill his place in 2008. It was only officially announced in 2010 that Josh was their guitarist. It's believed that his appearance on tour was a way of testing him out to fill Frusciante's role, but the rest of the band apparently did not know Frusciante was going to leave. Josh has shown his love of the band, particularly their early work, by often teasing songs they would never perform live in full. He does this considerably more often than Frusciante did.