At the end of the first episode of the two-parter where the Rockmores move away, when Kel arrives at the house after they've already gone, and it is revealed that his present for Kenan was a picture of the two of them together. This could also be considered a Tear Jerker.
Which makes their eventual reunion in the next episode all the more sweeter.
The fact that Kenan wants to continue being friends with Creeb(?) after all of that, knowing that, although he's an oddball, he's inherently a nice person.
Kel telling Ron Harper he still likes him even if he blames them for getting injured.
And Ron actually holds a press conference and says he's at fault for the accident making the public no longer hate Kenan & Kel
In the Christmas special, Kenan has enough money for the bike he wants, but gives it up for presents to give to another family. On Christmas Eve, his parents are proud of his sacrifice.
Then when Santa comes, he rewards Kenan by giving him the bike.
Kel saying he'll give Kenan half of his 64,000,000 Lottery winnings because he doesn't want to be a millionare without him. Kenan hugs him, not because of the money, but because he's so touched by the reason.
Kel fakes being Kyra's boyfriend to put the Alpha Bitch in her place.
In that same episode, Kel thinks it's Kenan's birthday and gets the whole audience to surprise him. Despite getting the wrong day (and the wrong cake), it reminds us that despite what they put each other through, Kel always cares about Kenan
In an episode where Kenan suspects he might have been switched at birth, he manages to track down the other Rockmore family he thinks he's actually related to, but when he gets to their front door, he realizes that he loves the family he's been with and would rather live with them than a family of complete strangers. It also helps that the other Rockmore family turn out to be Asian-American.