I am Jewish .. so here is what I say:
If I know you are not a Christian but not sure what else
HAPPY HOLIDAYS
If I know you are Muslim (this year)
EID MUBARAK NABE
If I know you are Christian
MERRY CHRISTMAS
If I know you are Jewish or something else that does not have their big deal holiday this tme of year (Buddhist, Hindu, Athiest, Zoro Astrian, Muslim (most years), non Euro-American culture ….
HOWSIT GOING