When I was in school, Gobseck by Honoré de Balzac was a mandatory reading. It's a story about a wealthy man who died without spending any of his wealth and living a very frugal life. It's a reminder that people should also enjoy the present and not live only for the future.
If you're even denying yourself a Christmas, then what sort of memories are you creating? Years from now you might look back and realize that you wasted your best years not doing anything, only waiting for Bitcoin to go up. And worse, when Bitcoin does go up, people often fail to take profits and then wait for the bull cycle again.
There can't be any objective rule for managing your Bitcoin investment, because value and time preferences are subjective. In some cases it could indeed be a bad idea to sell Bitcoin to buy a Christmas gift, in other it is not.