What Book/Series Lives Rent Free in Your Head (But in a good way)?

As the title says, I want to hear about the book that lives in your head, rent free, and you are happy that it is there to keep you company. Is it the first chapter book that turned you into a reader? Some book a friend gave you that opened up your world? One that was just really weird, but in a fun way?

Mine is Sara Douglass' Wayfarer Redemption trilogy (only books 1-3, I bailed on book 4 for REASONS)

This high fantasy trilogy is BUCKWILD in the best way and features:

• The Church is Bad Because it Won't Let Us Bang the Dragons (no dragons, but there are sexy winged people who are immortal and beautiful and down to get funky with anyone who makes eye contact with them but the Church taught everyone they were fuggo monsters because No Fun Allowed)
• A Guy Who Turns Into A Hawk For A While, He Gets Better
• Beautiful woman who talks to trees (the entire world depends on her talking to trees well)
• Beautiful woman who craves violence (the entire world depends on her doing a violence well)
• Sensible middle aged woman being a sensible, competent peasantfolk (the entire world depends on her being sensible)
• Some kind of bird man???
• A psychic baby getting punished with the ol' bloodline switcheroo (classic parenting move)
• The Gods' Most Tired Grad Student Who They Will Not Let Die
• A normal guy gets redpilled, it goes poorly for him
• Good ol' Shithead main man not deserving any of the women around him but he is also The Chosen One
• Is it magic, or is is radiation sickness?
• Charon is here, sort of, he's cool
• Cousin-kissin' HIGHLY ENCOURAGED for a particular bloodline of magic sexy winged people. Yes, incest is common in their family (no siblings/parents but pretty much everyone else is fair game, their family tree is a wreath)

It's a fun ride through the adventures, and despite my sarcastic bullet point list, I still love some of the characters to pieces. Tell me about YOUR book!