At Christmas, I put notes in lots of cards inviting people to come with me on the trail. Nobody responded, of course. (1.2.19)
This isn't like inviting someone to a wedding—attempting to trek the entirety of the Appalachian Trail is an extremely serious endeavor. It requires a heaping portion of chutzpah to even consider such a lofty feat.
In the twenty-five years since, I had run into him three or four times [...] We had remained friends in a kind of theoretical sense, but our paths had diverged wildly. (1.2.19)
In the end, Bryson is saved by the (kinda) lovable Stephen Katz. He might not be the most physically fit fellow in the world. He might not be the most quick-witted. And he certainly isn't great company all the time. But Bryson doesn't have any other options and beggars can't be choosers. Still, we don't think we'd like to be in his shoes very much.
Sometimes he would be proudly bearing my stick, which I had left by a tree when I had stopped to tie my laces or adjust my pack. (1.4.20)
Even though they butt heads at times, Bryson and Katz have a strong friendship. And Katz can be a solid dude at times—he makes it a point to look for Bryson's walking stick because he knows how important it is to him. That's friendship in a nutshell.
So I dined alone [...] It was a little odd to be without Katz after so any days of constant companionship, but agreeable as well, for the same reason. (1.11.98)
At a certain point, Bryson starts missing Katz when he's gone. And it's not just Stockholm syndrome. These two men are good companions even when they don't get along, as each looks out for the other's best interests. That's a valuable thing to have on the Appalachian Trail.
When we woke in the morning, dawn was only just leaking in but he had already gone. [...] We never did learn his name. (1.12.95)
This is par for the course as encounters with other hikers go. Although they touch each other's lives in meaningful ways, they never form relationships that match those between long-term companions like Bryson and Katz.
I told Katz where I thought I'd left it [...] "I'll get it for you," he said without hesitation and started to drop his pack. I could have wept again—he really meant it. (1.12.49-50)
That's our dude. Even though Bryson talks some serious trash about Katz at times (and with good reason, usually) he finds himself moved by the lengths Katz will go for the people he cares about. You might not want to get stuck in an elevator with him, but you'll sure want him at your back when things start going down.
At the airport, I realized we were already in different universes [...] so we parted awkwardly [...] When he was gone I felt bad, but then I [...] didn't think about him again for weeks. (2.13.10)
Despite the bond he builds with Katz on the trail, Bryson knows that they live very different lives. Bryson will go back to his quiet, quasi-British life in the countryside of New Hampshire; Katz will move to Des Moines for bone-breaking blue collar work. Still, these two dudes have shared a lot of pivotal experiences together, and that's got to be worth something.
I missed Katz, missed his huffing and b****ing and unflappable fearlessness, hated the thought that I could sit waiting on a rock till the end of time and he would never come. (2.14.9)
Bryson is reminded how much he enjoys spending time with Katz when he starts tackling the Appalachian Trail all on his lonesome. Sure, Bryson would probably be happy to have any companion (and he does indeed pick up a slightly boring Katz stand-in at one point) but the truth is that he deeply misses the singularly amazing and annoying Stephen Katz.
I stared in surprise [...] In all the weeks of camping together, it was the first time he had wished me a good night. (2.19.16)
Aww—looks like the Kool Katz missed Bryson too. To be honest, this makes us realize that we haven't discussed Katz' thoughts on their friendship yet. He seems to live a pretty lonely life, so he probably secretly treasures the time spent with Bryson.
I couldn't believe he was drinking again. It seemed such a deep, foolish betrayal of everything—of himself, me, what we were doing out here. (2.19.144)
The one thing that comes between these two bros is Katz' alcohol relapse. Although they eventually make peace—and Katz gets sober—this is a reminder that Katz' life is probably a little rougher than Bryson's. He might serve the role of "zany friend" with aplomb, but it's important to remember that he's a real dude with real feelings.