Good question and one which causes no end of discussion.
We are greedy here in Britain and Ireland. It's not enough for us to have Christmas Day celebrations we have more of the same on Boxing Day. Boxing Day is the 26th December and is a national holiday in the UK and Ireland and there are several reason why it is called Boxing Day, take your pick as to which one.
Boxing Day, like Christmas Day follows a traditional pattern, well at least in this house it does. We enjoy a long lazy full English breakfast followed by a good walk in the fresh air and crisp winter sunshine to blow off the cobwebs or visit family we didn't see on Christmas Day.
Home again to enjoy a few mince pies, Christmas cake and a glass of Port.
Boxing Day is a big day for sport, a form of the Boxing Day hunt still takes place despite the ban on full-on hunting a few years ago, plus there is always plenty of football and other sports to watch, which always keep my husband very happy.
Boxing day food and drink is less formal than Christmas day, usually, a buffet of leftover turkey and other trimmings, cold pie, pickles and the like and after all the festivities, probably and early night.