Disclaimer: I don't own Shingeki no Kyojin or anything else.
Day 2: Bertholdt
Bertholdt was in charge of decorating the tree for two reasons. First, he actually enjoyed decorating Christmas trees, and second, he was the only one tall enough to reach the top of the tree. Of course, it would take too long if he was the only one decorating the tree, so he enlisted some help.
And then promptly regretted it.
"Sasha! Stop eating the candy canes! They're supposed to be on the tree!" Bertholdt complained when he saw the brunette eating a candy cane while putting up ornaments. Chaos was everywhere as his squadmates argued about the correct placement of certain decorations, and finally Bertholdt had had enough. "Stop fighting!" After that, everyone calmed down and began working as a team.
Krista and Ymir were putting strings of lights around the tree, and Connie was putting the candy canes that Sasha had not yet eaten on the tree. Mikasa was carrying boxes of ornaments over to the group, and Eren sorted through the boxes afterwards. Armin was gluing together broken ornaments.
Eventually, the majority of the tree was covered, and all that was left was to place the star on top. Everyone gathered around the tree as Bertholdt carefully placed the star on top, and then loud cheering could be heard. As his squadmates commented on how beautiful the tree looked and chatted happily, Bertholdt smiled, glad that they had been able to work together. The end result would not have been as amazing as it was if they had not been able to sort out their differing opinions.