I got my Happy Season! card from my law school.
If you're not going to recognize what the season is, why send the card?
At least it's not as bad as the local TV ad I saw wherein the employees wished us all "a Happy Christmas, Hanukkah, Kwanza, or Ramadan - whichever holiday you celebrate." I about hit the ceiling. If you are going to be Uber-PC at least make sure that you know of what you speak.
First, Ramadan is a floating season and this year it wasn't in December; this year it started on 16 October and ended with Eid al-Fitr on 14 November. And technically it's not a holiday, it's a fast (although if you've seen the nightly parties in Middle Eastern countries during Ramadan you might wonder).
Second, if you are trying to hit major religious seasons such as Christmas and Ramadan you might want to substitute Yom Kippur for Hanukkah. Of course, it was on September 25 this year so it probably wouldn't fit.
Third, Kwanza. As best I can make it out Kwanza is a philosophical-societal-historical bonding holiday. As such it could fit with the others in a manner. But it's not a religious holiday so why mention it with them unless there is an underlying assertion that the three religious holidays mentioned are of faiths which exclude those who celebrate Kwanza? It is a disturbing undercurrent.
Yeah, I know, I shouldn't let these things worry at me but they do. I guess I am flawed. (in case you hadn't already noticed)
But at least I didn't get this upset.