Sam: you sing to yourself when you get bored. You'll sing anything to keep the boredom at bay, and he thinks it's the most beautiful sound ever.
Steve: you get really super nerdy sometimes. He likes it cause you get so passionate about it, and so you teach him all about it, and he loves learning.
Tony: you have a bad habit of drinking a bit when your stressed or angry or upset. And you get really needy when that happens, so he likes to feel like you need him.
Thor: you are always twirling your hair or playing with it some way. He finds it simply enchanting. Nuff said.
