I'm not one to order people around. I don't know all of the people involved. Maybe someone is having a birthday, but doesn't want it to be a happy one. Perhaps they would prefer to have a Really Unpleasant Birthday. What if they had their hearts set on having a Vexing or Trying Birthday?
So, Have Some Sort of Day of Some Kind Unless You'd Prefer Not To Do So, In Which Case, Don't.
I'm trying to find a Hallmark card that says that.