Have fun and smile. Look at each day as a good thing with a challenge. Find what makes you laugh and find what makes you smile. Even with a day full of challenges and disappointments you can find one thing that will bring you joy.
Maybe your coworker has a funny laugh. Maybe your spouse tells you they love you. Maybe your cat meows at you, or your dog licks your face. When you laugh and when you smile not only does it make you feel good but it makes others feel just as good. Have fun and smile.
Don't let sad people or angry naysayers take away your happiness, just have fun and smile. Do a dance, sing out loud, tell a joke. Have fun and smile.
One final thought, no matter how bad your day might be it won't last. So stay strong look for that Joy and have fun and smile.