Cold
The first Christmas Bumblebee experienced was with Sam. That was also the year that Tranquility was hit with the worst snowstorm it had ever seen.
It had come suddenly, unexpectedly, and Sam and Bee found themselves trapped in the garage until it ended, forced to spend Christmas Eve playing old board games and trying not to freeze.
When morning finally came, the storm over, Sam had absolutely no arguments with Bee's declaration that they were spending next winter somewhere warm and sunny.