Ghost of Christmas Present: There is never enough time to do or say all the things that we would wish. The thing is to try to do as much as you can in the time that you have. Remember Scrooge, time is short, and suddenly, you're not there any more.
Ebenezer Scrooge: How shall I ever understand this world? There is nothing on which it is so hard as poverty, and yet, there is nothing it condemns with such severity as the pursuit of wealth.
Ebenezer Scrooge: I hate life.
Ghost of Christmas Present: Nonsense, man! Why?
Ebenezer Scrooge: Because life hates me, that's why.
Ghost of Christmas Present: Scrooge, you're an even bigger fool than I took you for.
Jacob Marley's Ghost: You will be visited by three ghosts.
Ebenezer Scrooge: I... I think I'd rather not.
Ebenezer Scrooge: Who are you?
Ghost of Christmas Past: I am the spirit whose coming was foretold to you.
Ebenezer Scrooge: You don't look like a ghost.
Ghost of Christmas Past: Thank you.
Ebenezer Scrooge: May I inquire as to more precisely who or what you are?
Ghost of Christmas Past: I am the Ghost of Christmas Past.
Ebenezer Scrooge: Long past?
Ghost of Christmas Past: No. Your past.
Answer: Most likely because he's buying the shop's entire inventory. That would be shocking enough to explain his reaction.