One of the most underrated concepts is the power of saying “thank you.” It can feel like not saying it won’t make a difference and saying it may just be an automatic response, but it can make someone’s day better.

You never know who’s been yelled at, or who’s had a bad day, or who is feeling unappreciated. You never know the effect that "thank you" can have, even if it’s something as simple as holding a door or helping you reach something.

Harvard and UC Davis have done studies on the effect of “thank you” and found that there may be a correlation between happiness and expressing gratitude. The studies have mainly been performed on participants writing down what they’re grateful for and it raises their level of happiness.

I believe most people do like hearing that they are appreciated. It makes a difference to know that the work that you do is worthwhile and meaningful. Saying "thank you" can do something as simple as making someone's day better and as powerful as making them feel like they should keep going.

Although there are many people that believe a "thank you" can be implicit, or should only be said when something is really important, I think it matters more to say it whenever you can. Whenever someone has done something that makes your life more positive, say "thank you." Or thanks. Or some acknowledgment that they have helped you.

Saying "thank you" can help someone else, and it can shockingly help you feel better too. The world can be a happier place if everyone helped everyone, and saying "thank you" can be a great catalyst to continuing to help.

Everyone is much more inclined to do favors if they know that they will be thanked, and even if it is their job to help, like a waiter or a salesperson, it means something to say "thank you." Many people won't be grateful, and even the smallest gesture can make them work harder for the rest of the day.

So thank someone every now and again. It really can help everyone.