Part of having feelings is expressing them. When you’re expressing joy, happiness, contentment, enjoyment, etc. you may smile or laugh. When you’re not feeling those emotions and someone tells you you should be smiling or makes you feel like you should smile, that can be incredibly painful and awkward. It can take a whole lot out of you to fake that smile.
So today, smile for yourself when/if you feel like it! Honor ALL of your feelings and remember that no feeling lasts forever.