It’s the overreaction in this panel that’s funny. I mean, Gladstone just stubbed his toe on the doorstep - something that happens to everybody a hundred times a week but he goes:

“Ow! What’s this?! What’s happened to my foot?! It hurts?! Owwww..owww-”

And Scrooge’s done reaction is basically telling him nothing’s happened te yer precious foot, ye just stubbed yer toe, ye basic baby.