I've gotten a couple skull base surgeries (mastoidectomy - carving up behind the ear, peeling it back, and drilling that part of the skull open, and obliterating the air cells in the skull back there).
Nothing can really prepare you - it's scheduled so far out that you're worried for a while after scheduling, then you come to accept it. But then you get into the facility (hospital or surgery center or whatever) and you sit in the waiting room, and you're still not too worried. You get into the real surgery prep waiting room where you end up in a gown and shit and then you're kind of worried, but the doctor comes in and explains the operation and tries to cheer you up (which he probably will, having some reassurance from the guy who's gonna carve your head open is always good)......
..... But then they make you get on a stretcher thing and roll you into the operating room, and it's like 50 degrees and smells sterile and there's tons of equipment and a bunch of mostly apathetic people all doing routine checks of things and then it's kind of intimidating.
But you made it that far, so it's kind of like "fuck it, gas me up, let's do this, goodbye doctor and you 7 strangers". It's kind of an emotional rollercoaster. Ups and downs.
And then you come to hopped up on fentanyl with a big ass pad on your head and half of your face is numb and some cool person is rolling you on a wheelchair through the building and life is good. In a few hours you get dumped back into the world and you end up kind of missing that wheelchair pusher dude mainly because you were high as fuck on opiates when you first acknowledged their existence.
It's actually kind of fun.