Writing questions and answers

Show don't tell can have a lot of influence on the perspective of a story, and how the story/characters come across to the reader.

Let's start with the Harry Potter series (since you wanted a full novel, not just a paragraph)
Throughout the series, Severus Snape is built up as a bad guy. A strict teacher, petty grudge holder, former/not-so-former Death Eater, etc. This is both shown in his actions to others and is repeatedly voiced by numerous characters. And not just to make him a bad guy, but to prove Harry (and Ron and Sirius) right, and make them nicer and more sympathetic characters in contrast. It isn't until his final moments that Snape completely tosses the bad guy persona on it's head. If he had told Harry, with his last breath, that he wasn't a bad guy... Harry (and the reader) wouldn't believe him. He had to show Harry, with the vial of his memories, that everything he did-- including the good things that Harry didn't know about-- was for love of Lily Potter.

Now to turn it around, take Sherlock Holmes for example.
The story is written from Dr. Watson's perspective, so he can only write about what he himself experiences, or what other people tell him-- mainly what Holmes tells him. A lot of the mystery is tied up in "how did Holmes figure this out so quickly?" which Holmes usually explains at the end of the story. Holmes seems like some sort of crazy genius to Watson (and therefore the reader).
If you were to tell the story from Holmes' perspective, it would probably four times as long, and in-one-stream-of-conscience-run-on-sentence. The reader would also know the answer 2 minutes in, just like Holmes, and the rest would be boring details about how Holmes proved himself right. And then re-tell the whole thing to Watson when he got home.
As a piece of literature, Sherlock Holmes is a lot of tell, and hardly any show.
The recent films, for example, allow for a lot more show (a picture is worth a thousand words), and therefore a lot more of Holmes' perspective on the cases.

If this didn't make any sense, feel free to message me, so I can explain more fully.