In the extract, Scrooge is presented as ecstatic. This is evident when it says "Laughing and crying in the same breath". The use of emotively exaggerating verbs emphasise the feelings of greatness Scrooge is feeling. The exaggeration of such positive verbs effect the reader due to the surprise of seeing Scrooge react in such a way. This is because up to this point Scrooge had been presented as having no light whatsoever.
Dickens represents Scrooge as a changed man in the extract through his dialogue. This is evident when it says " I am as light as a feather, as happy as an angel, as merry as a school boy". The repetition of similes used by Scrooge is to compare himself positively, for example "Happy as an angel". This continuous over exaggeration allows Scrooges thoughts and emotions to stick with the reader, allowing them to always remember that Scrooge has changed.
This is effective because we get to see a change in the way Scrooge is presented, from the beginning of the novella. This is evident when it says "As solitary as an oyster". This quotation shows us that Scrooge was alone, mentioned as "solitary". This loneliness was presented in a way in which readers lacked any sympathy towards the character who was also described as "Squeezing, wrenching, grasping". This list exaggerates the negativity which consumed Scrooge at the beginning which makes his eventual changes so much more dramatic and surprising.
... and the ones that won't