Everyone knew that you came from a dysfunctional home, without the affection, love and childhood that a child should have. This is clear in your distant behavior, when you fail to return Richard's warm hug, always retreating, or when you mutter a dry 'thank you' when receiving a gift or compliment from Bruce, and avoid interactions with them, often not even eating at the table.
They know that you don't act like that because you don't like them, you just don't know how to reciprocate a feeling you don't know. But even though you're a closed and sealed book, they've noticed - or rather, Tim has noticed - that you always notice the houses' Christmas decorations when you're on patrol. At first he thought you were judging the extravagant decorations, but you didn't have a look of judgment in your eyes, but rather...fascination. This sparked something in Drake's mind, and he ended up sharing it with the others in the Bat-Family, which resulted in where they are now, putting up a huge Christmas tree, some not wanting to be there, others actually having fun.
You're so focused on trying to untangle the blinker wires as if your life depended on it. They finally managed to find something you liked, you even said more than three words!
“Who chose this horror of a tree? It's too big!" Damian complained.
“It has to be big so that everyone can decorate a little in their own way.” Stephanie said, appearing with Cass and Duke, each with a box of decoration.
“It will be the ugliest tree in Gotham.” Demian scoffed, receiving a reprimanding look from Barbara. “What?”
“We need a song to get us more into the Christmas spirit.” Dick said, as he had a garland wrapped around his neck, and then All I Want For Christmas Is You started playing. "Now yes!"
“Where is Jason with the rest of the boxes?” Tim asked.
"I am here." Jason said gruffly, placing a huge box on the floor. “You’re messing this up even more.” He grumbled, but he decided to help you with the blinker.