Did you know? PF – pour féliciter (New Year’s congratulation, in Czech and Slovak only) https://en.wiktionary.org/wiki/PF

PF: a unique Czech and Slovak version of Happy New Year

It is almost time to start sending out Christmas cards. In Czech, the phrase “Merry Christmas and a Happy New Year” is often abbreviated as PF 2016. The abbreviation is French and stands for “pour féliciter” – which is a phrase that is not used anywhere else. Not even in France…

…at least according to Wiktionary. The origin of this phrase in the Czech language is disputed. One theory says that it was first used centuries ago when noblemen spoke French (it was a part their “higher education”) and it somehow survived.

However, the problem often arises when companies send out their corporate greeting cards to their foreign partners – and they leave the “PF 2016” in the foreign-language version, along with the proper “Merry Christmas…” wish. Foreigners have no idea what the initialism means…

https://czechdaily.wordpress.com/2010/12/03/pf-a-unique-czech-version-of-happy-new-year/