Sam seeing Cat in trouble, having no idea who she is, and running to her rescue. Coming from Sam, that's rather selfless.
Sam giving Cat all the babysitting money, even though Cat would've been perfectly happy with the small percentage she'd just given her.
Sam has quite a few in "#FavoriteShow". The first is that Sam wipes Cat's tears and tries to cheer her up, followed later when Sam has the entire set of "That's A Drag," Cat's favorite show, delivered and set up in their apartment.
Cat hugging Sam in #NewGoat out of fear of being separated and then again after Sam assures Cat that nothing bad will happen.
The Opening Theme consists of the two geeking out and having fun from later on in the series. Knowing Sam from iCarly, it says a lot about how must she like Cat.
Dice's reason for dancing at a birthday party in Secret Safe is because he's trying to afford a new laptop for his mom. Sure, it may not excuse lying to Sam and Cat and locking them in a safe, but still.
Despite Dice locking them in a safe, Sam and Cat were still willing to lend Dice money after they learned Dice dances for money sometimes. However he's still punished.