Exactly what the title says. They can be funny, random, deep, sad -- anything, really. If you'd like, it'd be nice to also add why you like the quote so much.
Some of mine are:
"Deadlines just aren't real to me until I'm staring one in the face." from The Lightning Thief by Rick Riordan,
"People are more difficult to work with than machines. And when you break a person, he can't be fixed." from The Battle of the Labyrinth by Rick Riordan,
“You step into the Road, and if you don’t keep your feet, there is no knowing where you might be swept off to.” from The Lord of the Rings: The Fellowship of the Ring by J.R.R. Tolkien,
“He'd been wrong, there was a light at the end of the tunnel, and it was a flamethrower.” from Mort by Terry Pratchett, and, lastly,
“So, not expecting to see anyone, he failed to do so.” from The Ruins of Gorlan by John Flanagan.
I like the first two because they feel horribly relatable -- I procrastinated on an art presentation for a good deal of this and last week, and I often wish people could just work in a way that would make sense to everyone. The third sounds beautiful and makes me feel like a child again, thinking about how wonderful everything out there is. The fourth is a classic Terry Pratchett joke (honestly, I like anything he writes, and there are way too many lines in his books that made me giggle while reading them) and involves flamethrowers, so it's obvious I like it. Finally, the fifth one has the perfect Ranger's Apprentice vibes with just a bit of dry humour to top it off.
Anyways, that's all for now, see you later!