The person celebrating alone can still make the day feel deliberately inhabited.

Marking a day by yourself is not a lesser version of a day marked by others. Choosing the meal, going somewhere on purpose, doing the thing you actually like rather than the thing that suits a group, all of it makes a day inhabited rather than merely survived. What gives an occasion weight is intention, and intention does not require an audience. Company changes the shape of a celebration and not the fact of it.

If a date is coming that you will spend alone, decide now what goes in it rather than letting it arrive undecided. One planned thing you genuinely want is enough.