The term "book hangover" shows up in the Urban Dictionary!
When you've finished a book and you suddenly return to the real world, but the real world feels incomplete or surreal because you're still living in the world of the book.
I just finished the last book in a trilogy, Dreams of Gods and Monsters by Laini Taylor, and I'm going through a bad book hangover. I don't want it to be over! I want prequels and sequels and spin-offs! I want more mythical creatures, more clashes between our world and Eretz, a fantasy parallel world. I want more of the characters: Karou and Akiva and Liraz, Zuzana and Mik and even Fake Grandma and the White Wolf. I want more of Prague and Morocco and Rome, and the Kirin caves and Astrae and the Far Isles. Chimaera and seraphim, Stelian and stormhunters.
But more of what I want is not likely to show up for another couple years, if ever, so in the meantime I'm chewing over just what drew me so much into this series. I've read several very good series over the years but only one other (the Lord of the Rings) has gotten under my skin as much as this one.
Things that drew me in both series, the Smoke and Bone series and Lord of the Rings:
1) rich world building, including mythology
Both Eretz and Middle Earth have different sentient races, cultures, traditions, rich histories and mythologies and languages. Middle Earth also had a detailed geography (Eretz needs a map! please, Ms. Taylor, make us a map!) I've started other fantasy series that have similar world building richness, such as Game of Thrones, but was never tempted to finish the series, so there's something more than excellent world building
2) epic scale
Nothing short of the entire world (or even worlds, plural) is at stake and there is a generational aspect to the story, with a long history of conflict.
Can Aragorn reclaim the lost throne of Gondor that is rightfully his, but so much stands in the way? Can Karou and Akiva realize their dream of peace finally, the end of the thousand year war between their races?
4) longing stories
Not just love stories, but longing stories (and stories, plural). Aragorn and Arwen, Eowyn and Aragorn and Faramir; Akiva and Karou, Ziri and (spoiler). Longing for other things too, like the the elves longing for the West or the dwarves for their lost Moria. Karou longing to know who she is in the first book, Eliza longing to know who she is in the third book. These books convey a deep pathos, a twining of love and loss and sacrifice.
5) layers and intertwining threads
My head spins trying to think of how the authors fit together all the layers of stories throughout the series, with complicated histories and prophecies and twists, set-ups, and implications.
6) family, friendship or fellowship
The nine in the fellowship of the ring (including the one traitor) and all their different personalities and quirks and a little bit of picking on each other or one-upping each other. Zuzana and Mik and Issa as Karou's friends and foils and Hazael and Liraz as Akiva's.
7) laugh out loud moments
No explanation needed.
Other admirable series I've read:
Iron King, Iron Daughter, Iron Queen, and Iron Knight by Julie Kagawa
Sabriel, Lirael, and Abhorsen by Garth Nix
Girl of Fire and Thorns, The Crown of Embers, and The Bitter Kingdom by Rae Carson
Wings, Spells, Illusions and Destined by Aprilynne Pike
The Harry Potter series, of course
The Mitford series, by Jan Karon (not fantasy, but arguably just as much world building!)
Series I plan to finish:
Grave Mercy, Dark Triumph, and Mortal Heart by Robin LaFevers
The Temeraire series by Naomi Novik
Shadow and Bone, Seige and Storm, and Ruin and Rising by Leigh Bardugo
The Archived, The Unbound and hopefully a third book by Victoria Schwab
The Queen's Thief series by Megan Whalen Turner
Have you ever had a book hangover? and what kind of literary cocktail caused it? (grin)