In one episode of the Sonic the Hedgehog 2006 race, Max says (jokingly) that if Dan beats Radical Train first try, he'll slit his throat. Dan asks him to please not, because "I actually sort of like you".
We also learn during said race that, as a birthday gift, Max sent Dan a Wii U. (And the copy of Sonic the Hedgehog 2006 that he's using to record.) And in part 9, after jokingly offering a deal to give Dan ten dollars for Hyrule Warriors in exchange for Dan dying in the game, Max says he'll send the money anyway.
Throughout The Walking Dead, Max has consistently chosen the options that let him kill a character, with two "exceptions" - the first time, the character suffered a Fate Worse Than Death due to incoming walkers (and it had been the result of a coin flip anyway), and the second time, it was being pragmatic by not giving someone a Mercy Kill and attracting attention. The first time Max outright subverts this and chooses not to kill a character or let them die, just because? Saving Ben in episode 4. After having clearly disliked him in episode 3, and only just starting to feel more neutral about him this episode.
Adding onto that, Ben willingly joins up with Lee at the end of the episode after Max leaves the choice up to him. Granted, Kenny doesn't join, which kind of ruins it...
And while it crosses with Tear Jerker, the fact that Ben's eventual inevitable death is what finally pushes Max over the Despair Event Horizon is further heartwarming, showing his attachment to Ben.
Max makes two teams of "people who are awesome". These teams consist of worms named Rhino, Enigma, Dan, Zero, Peter, Spark, Jero, and Tim; ironically, all people whom he is Vitriolic Best Buds with.
He also says that there were people he couldn't fit because he only did two matches like that and there were only four worms per team. He mentions people such as David and Wren as being ones he couldn't put on.
In the "Tabletop LP" of Mastermind, the death of Monty Oum is brought up. Both Max and Peter appear mournful of his loss.
Being the huge Fallout fanboy he is, you can just imagine how psyched Max was for the Fallout 4 announcement. How he acts in the "reaction and thoughts" video in response to the trailer is like one big optimistic Squee! (even though he has some reservations about getting his hopes too high).
You can also see him hugging a Litwick plushie the whole time. Awwww.
Max got annoyed with people bugging him to make Cutie Mark Laboratories and stop making let's plays, and posted on Twitter some irritated tweets about it. Tim, Dan, and Spark then all replied with their own input.
Tim: Those people who tell Max to quit let's plays is basically telling him to say "fuck you" to playing with us, his friends. Nice job
During an episode of Fibbage, Pip (Max's cat) paws at his door. He immediately lets her in and spends the remainder of the video playing with her.
A similar thing happens during Twilight Princess.
While it ultimately didn't go well, Spark being willing to drive down to Canada to pick up Max for BronyCon 2016. It was about a twenty-hour round trip and he was more than willing to do it.
On the topic of conventions, earlier that year, Max went to Pax South for little reason other than visiting Jero.
At one point during a GTA Online heist, Jero takes a shot at Dan's Hair-Trigger Temper by calling him "Courier Salt". Max immediately jumps to his defense, firing back at Jero for his causing of delays and pauses in recording.
In the second season of Minecraft Hardcore, Jero grows hostile towards Max when (he thinks) the latter let Tim die. When he goes too far, Peter jumps to Max's defense to get him to knock it off.
Max and Peter have an earlier moment; when they go venturing for a desert (which in itself is a heartwarming moment, as literally the only reason they're looking for one is to get cactus for Rhino's banner, which has no actual importance to the hardcore), they chat about casual things and reminisce about the early days of the two of them playing Minecraft together. After the two rarely interacted in the first season, it's nice to see them just shooting the shit as they wander around relatively peacefully, especially if you miss how often videos just featured the two of them in the channel's very early days.