The narrator of Tuck Everlasting sure doesn't have an opinion about anything. How do we know? Well, even when describing the slimy man in the yellow suit, she holds back commentary. Take a look at all of Chapter 13 for an example, or if you're feeling lazy at the moment, we'll give you a taste:
The man in the yellow suit took off his hat and smoothed his hair with long white fingers. Then he knocked at the door. (13.1)
Shmoop's going to rewrite those sentences with our biased opinion of Yellow Suit Guy in mind:
The man in the yellow suit, his brain full of schemes, took off his hat and smoothed his greasy hair with long, white, menacing fingers. Then he smirked, knocked at the door, and waited to pounce.
Quite a difference, right?
To be honest, we're kind of grateful that the narrator doesn't have much of an opinion, because it lets us make up our own minds. Throughout the novel, we (and Winnie!) get five different characters telling us their opinions about living forever—but it's up to us to decide how we feel about it.
P.S. Natalie Babbitt said this was intentional. She's awesome like that.