Rant: I hate saying "Merry Christmas" and "Happy New Year"

Rant: I hate saying "Merry Christmas" and "Happy New Year" Especially when people say it to me in passing, I can never say it back smoothly. I feel like I come across as a bit of a douche when I don't wish it back, it sucks so much. I always just nod my head, and sometimes am able to get out a "you too!", but I can never fully greet them.