What's the big deal?

I was fortunate enough to not have to work Thanksgiving, Christmas Eve, or Christmas day this year. I am lucky that most of the people I work with want to work the holidays for the extra holiday pay.  Anyway, I worked last night, New Years Eve, from 6 pm-1:30 am since I had the other 3 off.  Anyway, I didn't go to bed right away, so I was up pretty late.  I woke up this morning and got myself and the kids ready for the day and we were out the door at 11:30 to go to Sophie's tumbling class.  I get to the gym and see that they are not open... luckily the kids didn't freak out cause they really hate when things don't turn out the way they expect. It was so cute though because Nolan says to Sophie in his nicest voice "I'm Sorry Sophie, I promise we will do something fun today".  So, my question is, what's the big deal about New Years Day? I really don't understand why so many places are closed. It's just a day... not that I'm religious, but Christmas and Easter are religious holidays, Thanksgiving is celebrating the pilgrims and the feast etc. but New Years Day is just the first day of the year.  Are we off so anyone who stayed out too late can sleep in and recuperate after a night of drinking? I don't know if I feel this way because Poy and I have always worked in a business that doesn't close or what... but I just don't get it.