Simple topic for today: just smile more. It makes you look more attractive, it is said that it improves your health, it can make you a better leader (because smiling encourages trust), but most importantly, it will make you happier. Smiling tricks your brain into releasing endorphins, which lowers stress and improves your mood.
This is just a fun fact, not something actionable: smiling is one of the few nonverbal or body language behaviors that is the same across cultures. Charles Darwin did a lot of research around smiling. He noticed that babies that are born blind smile the same way as sighted infants do, and therefor he concluded that it is “built in” instead of learnt.
A real smile is hard to fake, but even a fake smile will give you the positive effects attached to smiling. If that (beside the fact that smiling is great) is not a good reason to show more teeth, I don't know what is.