Happiness is infectious. Get up and start an Epidemic.
This morning, I greeted a friend of mine with a hearty, “Morning, sunshine!” - literally moments later, the sun poked through the clouds after an entire week of rain.
This is probably a dumb analogy to most, but I think it’s symbolic. Fight through the sadness, stress, fatigue, pain, or whatever is afflicting you, and try to spread some cheer anyway. You never know what it will do or who it will touch.