Quote 31
Al and I meet eyes, like we usually do when Will and Christina start to fight. But this time, the second our eyes meet, we both look away. I hope this awkwardness between us doesn't last long. I want my friend back. (16.37)
Tris may be living in a dystopian Chicago where everyone is in some faction, which is totally unlike your life. But here she is experiencing something that you're probably familiar with: she's sharing a secret look with her friend Al, but it's an uncomfortable look because he like likes her. How very ordinary.
Quote 32
The articles troubled me, but I had friends to cheer me up, and that is something. When the first one was released, Christina charmed one of the cooks in the Dauntless kitchens, and he let us try some cake batter. After the second article, Uriah and Marlene taught me a card game, and we played for two hours in the dining hall. (21.6)
Since Tris isn't used to having friends, she makes some statements like this that make it pretty easy to see where the theme of friendship pops up. When something bothers Tris, she has friends to help her. So we could say that, in Divergent, friends are people who cheer you up.
Quote 33
I don't need them—but do I want them? Every tattoo I got with them is a mark of their friendship, and almost every time I have laughed in this dark place was because of them. I don't want to lose them. But I feel like I have already. (21.113)
Real talk: sometimes friends can get you down. Because they're all competing for the same thing, Tris and her friends sometimes fight—both literally (when they're punching and kicking in the arena) and, well, literally in a different way (when they're arguing about whether they can trust each other). Friendship sure is good and bad mixed together.