Apostrophes are tricky in holiday correspondence. With just one small mark, they can make the difference between an error-free card and the alternative. Adding an apostrophe to “Season’s Greetings” is correct, since it makes the phrase possessive. (As in, the greetings belong to the season.) Whereas “the Bakers” is correct as it is. If there were an added apostrophe (as in, the Bakers’ or the Baker’s), it would make the term possessive. This is incorrect, since there is no subsequent noun for the Bakers to take possession of in the phrase.