An ordinary smile can change how a tired face is read without changing its tiredness.

Expression and condition are separate things. A smile restores nobody’s energy, and it does change how the next person interprets what they see, which shifts the tone of an exchange that might otherwise have begun with an apology. That is worth something and it is not a cure. The tiredness stays exactly where it was.

Use this in both directions. Offer the small warmth when you can spare it, and do not demand it of yourself when you cannot. When somebody manages a smile through obvious exhaustion, take it as generosity rather than as evidence that they are fine.