You haven't seen Psycho? Really? You should see it as soon as possible before someone spoils the ending for you. Even if you haven't seen it and you don't know the end, I imagine you know about the scene in the ... oh, I don't know whether to mention it or not...perhaps not.
Let's just say that it stars Janet Leigh as a young woman who steals money from her employer, and flees in her car. Her journey is rather more eventful than she would have preferred.
One of the things that made Psycho such a successful thriller, was that it took its audience completely by surprise. Many of the techniques used have often been copied by modern film makers, so the surprises might not shock viewers the way they used to, but it still worth seeing before someone tells you about the...oops, nearly!