Happy New Year kan, såvitt jag vet, användas även efter nyårsafton. Vad gäller "season's greetings"/"seasonal greetings" så förklarar Wikipedia hela saken mycket bättre än vad jag kan: http://en.wikipedia.org/wiki/Christmas_and_holiday_greetings#Season.27s_Greetings "Season's Greetings" is a greeting more commonly used as a motto on winter season greeting cards, and in commercial advertisements, than as a spoken phrase. In addition to "Merry Christmas", Victorian Christmas cards bore a variety of salutations, including "Compliments of the Season" and "Christmas Greetings." By the late 19th century, "With the Season's Greetings" or simply "The Season's Greetings" began appearing. By the 1920s it had been shortened to "Season's Greetings,"[10] and has been a greeting card fixture ever since. Several White House Christmas cards, including U.S. President Dwight D. Eisenhower's 1955 card, have featured the phrase.[11] Some[who?] believe that the "Season" in "Season's Greetings" is referring to the Christmas season. Consequently, some[who?] consider the replacement of "Merry Christmas" with "Season's Greetings" as an attack on the Christian elements of the Christmas holy day. Others[who?] claim it is commercially-motivated pandering to a greater consumer base hoping that avoiding overtly Christian or Christmas messages will spur shoppers to spend, regardless of any religious overtones. (see also: Christmas controversy) A differing opinion claims the phrase "Season's Greetings" is more neutral and avoids any implication of one "holy" day's dominance over another. It may be used to be more inclusive of other winter holidays (such as Kwanzaa or Hanukkah), or to acknowledge the possibility that the reader may be non-religious.