Tis The Season To Say Strange Things

Christmas really is the most wonderful time of the year and it is so special that we seem to have words which we only hear uttered this time of year.
At no point in the other 11 months of the year do we deck anything, in January to November we just decorate, adorn or even furnish our hall but in December it is specifically 'Decked' and Figgy Pudding sounds like something full of Figs, which it isn't, no Figs were in it whatsoever but why we sing about it in the song and not change it to Christmas Pudding is a strange one, both have four syllables so swapping out Figgy for Christmas would still scan.
We don't listen at Christmas, we 'Hark' be it we are harking Herald Angels sing or the neighbour singing 'I Wish It Could Be Christmas Everyday' in such a way that Roy Wood would sue them.
An animals feeding trough is a manger for the month and we turn our dictionaries back to the 16th Century version to say 'Ye' and how 'Tis the season to be Merry' which leads to the question why can we only be Merry this season? Can't we be Merry in Summer or Spring or can we only be Happy in those Seasons?   
Wassailing sounds like some sort of torture although if you had me me massacre 'O Holy Night' then you would probably agree but Caroling sounds much better and how much jollier would the News sound if was called Tidings.
It is also the only time of the year that you can hum along to a Cliff Richards song without dying of embarrassment if someone over-harked you.