If you think this job is going to be easy, you're in for a 'rude shock'. [=you will be unpleasantly shocked when you find out that this job is not easy at all]
He's about to have a 'rude awakening'. [=he's about to find out something that will shock him unpleasantly]
I was 'rudely' [=suddenly and unpleasantly] awakened from my nap.
(..) My friends, welcome to Kattegat. And who might you be? My name is Ubbe. Forgive me, Ubbe. If I'd known, I would never have been so rude. Your father was a great hero. Perhaps the greatest hero of our race. And that is why we have answered your summons, (..)2017 TvShow: Vikings Title: The Great Army Season: 4 Episode 17