I was in this situation a few years back. I won't go into details, but it was family issues beyond my control and I just wanted to fuck the whole day off.
I had a bottle of champagne in my drinks cabinet for months, so I stuck it fridge the day before and went and got a beautiful Indian takeaway on the day, which I had with the champagne on Christmas Day evening, whilst watching loads of trashy TV alone. It was very liberating.
Christmas the following year I wasn't bothered about, for similar reasons, so I went and volunteered at a local homeless Christmas meal event. Which was really fulfilling for all involved.
That same evening I had my now DP over, plus a friend who was going to be alone due to a relationship breakdown and not coping well, and we had a lovely meal, very relaxed, not OTT Christmassy.
Last year I didn't put a tree up because of mega work pressures and 14 hour days in the days before and had another chilled day with DP.
As long as you're happy with how you spend it, ignore others or what's supposedly expected / the 'right way' to spend it. It's just another day.