It all depends on what job they do at the Post Office whether they have to work the holidays.

My brother works at the main St.Louis Post office downtown as maintenance on the sorting machines..

He was "drafted" into working both all the holidays this year, Christmas Eve, Christmas Day, New Years Eve and New Years Day.
Whats really kinda crappy is that he normally has Thursday and Friday off, they are his normal scheduled days off so he was required to work what is his normal weekend along with his normal work week.

Up until the recent retirement of all the highest seniority guys who all opted to work all those holidays for Triple time he never had to work them.
He has 18 years in and he was the lowest seniority guy on his shift so he was given no choice.

He doesn't want to work them, he doesn't want or need the extra $$$$, lets just say that he isn't happy to be forced to work them.