The Watsons definitely aren't a passive bunch, and we learn a lot about them from what they do. Think about Dad: rather than losing his temper with Byron over the conk, he chooses to cheerfully shave Byron's head. Or what about Joey, who simply cannot allow Momma to burn Byron, no matter how many times they talk about it. And then there's Momma, who packs extra sandwiches for Kenny after she hears about Rufus and Cody. The Watsons may be weird, but these actions reveal that they are also solid peeps.
That Kenny is one perceptive dude, and Shmoop is pretty psyched about it. Without Kenny giving us his insights, we'd miss more than a few things about our characters. For example, it's Kenny who points out in Chapter 8 that Dad is sensitive, and it's from his observations that we know Momma is worried about money, especially now that they are taking this trip. He also notices when Joey is upset by the angel Mrs. Davidson gives her, and he can tell there's something bothering Momma about Mr. Robert. We could go on, but we think you get the point. Kenny's keen eye catches all sorts of important details that help us better understand the characters' feelings, motivations, and personalities.
We also learn about our characters based on the role they play in the family. For example, we decide how we feel about Byron based largely on how he treats the family, and we tend to like Joey because she's always trying to protect everyone in the family. The Watsons' family interactions tell us that Dad is the jokester while Momma is the one you really have to worry about when you're in trouble. In fact, take a look at this scene from the very first chapter:
"The fly was still stuck and buzzing.
"Oh, Mom-ma! Hel' me! Geh me offa 'ere!"
"Oh my Lord!" Momma screamed, and I thought she was going to do one of those movie-style faints, she even put her hand over her forehead and staggered back a little bit.
Joey, of course, started crying right along with Byron.
Dad was doing his best not to explode laughing. Big puffs of smoke were coming out of his nose and mouth as he tried to squeeze his laughs down. Finally he put his head on his arms and leaned against the car's hood and howled. (1.104-107)
Okay, so Byron has frozen his lips to the car. How does this family respond to an emergency situation involving one of them? Kenny gets help, Joey cries, Momma worries (and ultimately solves the problem, we might add), and Dad cracks up. The way these characters live as a family tells us pretty much everything we need to know about them. That's the Watsons in a nutshell.