So Magicka is a game with a lot of subtle (and not so subtle) references to popular culture. But one thing has bothered me back when I played and I failed to figure it out - Vlad would often finish his dialogue by saying Good "Luck"! with the word Luck always shown under quotes.

What is the reason for this? Is this some reference I can't figure out or just a random joke of some kind?

Edit: some possible spoilers for the first game story in the comments of this post.