What book could you read over and over again?

My favourite book that I go to when I’m in need of a pick me up, want to read but don’t want to properly think is Feet of Clay by Terry Pratchett.
It’s my favourite of all the Discworld books. Please don’t ask me to explain why. It’s too complicated, but Feet of Clay wormed its way into my soul many years ago and stayed there.
I often re-read the Discworld books, but that is the one I pick up the most. I’m currently re-reading Snuff for what seems like the millionth time. I wonder how many times I have actually read the series…