Performing at a fan's bat mizvah instead of going to the pre-Grammys press junket and party.
When being given a book of fanart and such from a girl who created a fan project, he said he felt like an asshole for not having anything to give the fan in return.
Throwing a Starship wrap party in Vegas for his Team Starkid friends because he couldn't make it to every single performance of the show.
Darren giving his friend Brian Holden, of Starkid fame, a hug during Darren's performance of "Silly Love Songs", in Chicago, for Glee Live!
Pretty much anytime Darren performs and one of the Starkids are there, he'll acknowledge them or ask them to perform a song with him. Joey Richter, Lauren Lopez, Dylan Saunders, and Joe Walker have all performed their signature AVPM songs with Darren.
Darren + Starkids = Heartwarmness again, this time at Leaky Con, at the end of "Home" specially, where they all hugged him.
Definitely this performance of "Teenage Dream". If you were a fan before he became famous it's also a HUGE Tear Jerker.
Upon meeting Kellen Sarmiento the mini-Warbler, Darren went over to give him a hug. The fan screaming got even louder during those eleven seconds.
Darren is such a genuine all around nice guy that it seems as if just the way he acts on a normal basis without even trying to could fit under this, for example in this red party event, it's a red party event, and he's talking about something as trivial as Chord Overstreet's gold shorts while being charming. Throughout he has his arm around Lauren the whole time, and clearly isn't being weird or strange about it, and is just having a good time hanging out with her and seems to just be generally making her feel beautiful. It doubles when you realise that the other cast members and the interviewer flock over because of Darren but he never leaves Lauren's side. Lauren, like her character on the show has Downs Syndrome.
This love letter to all of his fans, which really demonstrates the humility and level-headedness that make Darren so totally awesome.