Ciel taking in Snake, despite lying to him that he was looking for his friends when said friends had attempted to ambush Ciel's mansion and were killed by Ciel's staff. However in later chapters, it's shown that Ciel does geniunely care for Snake, such as the brief encouragement he gives to Snake when other people were mocking his appearance. Also, he told Snake to get on the rescue boats in his place.
Season 2 Episode 11: Alois (in Ciel's Body) asking Hannah to tell him that she loves him and give him a hug. Which he's always needed. She does both, which prompts him to cry tears of joy and say "Love is...warm, isn't it?"
In episode 1 of season 2, Alois begs Claude not to leave him alone, and Claude holds Alois's face in his hands and declares he'll never leave him alone.
Alois's final wish results in Ciel's immortality. Aww!
Sebastian's and Ciel's exchange at the end of chapter 65 of the manga. This is the first time we have seen Ciel being genuinely concerned about Sebastian and treating him with kindness. True, Sebastian is a demon, but the little scene at the end is very sweet nevertheless.
In chapter 66, Ciel cheats during the egg hunt by pretending to have an asthma attack in order to distract Soma and Agni. Their reaction after losing because of his ploy? They are happy Ciel is well.
In chapter 70 MacMillan going into Ciel's bed to be next to him while they have their talk.
After learning that Ciel has been aiming for the batter's face in Cricket the crowd starts booing about blue house's poor sportmanship. How does the P4 of the oppossing team, the power based green house, respond? Greenhill gives the crowd a reason you suck speechdefending Ciel's actions on the basis that aiming for someone's face requires a lot of practice and the use such underhanded tactics is just proof that blue house really is serious about the tournament winning this year.
Agni's backstory. The son of a corrupt brahmin, he spent his life indulging himself and casually breaking the law until it came down on him. As they prepared to hang him, Soma - for no reason other than his own whim - jumped onto the gallows platform and saved his life. Agni's Undying Loyalty suddenly makes a lot of sense.
"And at that moment, God appeared."
Chapter 91, Finny's flashback and speech to Ciel.
The story about when Ciel gave Finny his name is really touching. Especially since having a name means so much to Finny: his name has given him a whole new identity and allowed him to become something more then a disposable test subject. "You taught me how to grow," indeed.
There's one chapter where the Phantomhive three are talking about how far they've come, and how much they owe Ciel and Sebastian. Doubles as a tearjerker, because none of them have any idea that Sebastian's a demon, but it's still touching to see how they feel.