Fred isn't phased by his uncle- 'Don't be cross uncle'.
He is very happy about Christmas- 'A Merry Christmas, uncle! God save you!'.
He thinks that Scrooge should be happy at Christmas- 'What reason do you have to be morose? You're rich enough'.
Why does he visit Scrooge and how does he respond to Scrooge's negativity?
He tries to make him think more positively- 'What right do you have to be dismal?'
Fred visits him every year to try and cheer him up- 'Nay, uncle, but you never came to see me before that happened. Why give it a reason for not coming now?'
Fred fights back after he was called an idiot- 'Keep it! But you don't keep it.'
There is a contrast between Scrooges negativity and Fred's positivity.
Fred visits him every year as Scrooge doesn't make an effort to visit him.