The Headmistress at The Common Room asked about books which had broken our frozen seas. She was referencing a Kafka quote,
A book ought to be an ice pick, to break up the frozen sea within us.
I answered her in a comment, but wanted to put them on here, and add to them as they came to me.
"Stranger in a strange Land" (Robert Heinlein) changed my world, and changes it every time I read it and "grok" more of it, perhaps never to a fullness.
The Bible, odd as that sounds, (or perhaps not) is able to unlock me when I'm stiff with emotion, usually Proverbs, because they are either very true or very funny. The advice I find within that book answers every question for me in different ways.
"Brave New World" (Aldous Huxley) also rocked my world alongside "Running Man" and "The Long Walk" by Richard Bachman, aka Stephen King. The first two are becoming more and more evident in the world, the latter is just one of the strangest books I've read in a long time.
I will add to this.
Although part of me says "Those ones came to mind straight away. Maybe *they* are the ones that matter."