All the necessary ingredients were purchased and waiting by the door. I was 12 years old and ready to open my first retail business: a lemonade stand at a local farmers' market. Who doesn’t like an ice-cold glass of sweet lemonade in the middle of summer?

On that particular day, though, a cold front swept through Brighton, Mich., and the temperature was a brisk 38 degrees. Before I left the house, my mom declared the unfortunate reality presented by the weather and the probable failure of the lemonade stand. She asked very bluntly if I was sure that I still wanted to go ahead.

I just smiled, nodding my head. Indeed I did not sell any lemonade that day, but I manned my booth and walked away with 100 crisp American dollars. I showed up with a smile and discovered that attitude is truly the most awesome tool a person owns. Customers wanted to reciprocate my joy with a small offering and for my lemonade stand business that day it came in the form of tips, not purchases.

Related: Revive That Old-Fashioned Extra: Excellent Customer Service

Studying the smile phenomenon. Smiles have an effect on those who receive them. “The presence of a smile may provide an important signal that a reward is or is not attainable, " according to a 2003 study in NeuropsychologiaThe simple, often spontaneous flexion of facial muscles, combined with a slight tightening of the skin around the eye sockets, can literally make other people feel like they are winning. As smiles are contagious, this sentiment of reward is passed along to the next unsuspecting soul.

Psychology Today article explained the functional usefulness of stretching  the mouth into this position. “Each time you smile at a person, their brain coaxes them to return the favor. You are creating a symbiotic relationship that allows both of you to release feel good chemicals in your brain."

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Examining the business impact. From a business perspective, what could be more essential than a smile? It creates a jovial base of clients who will continue using the service and feeling good about it. The more the business owner smiles, the better the clients feel. The better they feel, the longer they live, and the longer they continue being loyal customers.

In my various roles in the service industry, I tested this science of smiling. Then when I found myself working a 9 a.m. to 5 p.m. corporate sales job inside the four walls of my office, I was shocked to discover that a smile still could be important, even when customers couldn't see my face.

Needing an outlet of entertainment, I started to play around with the inflections and intonations of my voice, speaking with a big smile painted across my face. Colleagues who passed my office certainly questioned my sanity, but orders came through and appointments were being made. By starting with a smile when I called people on the phone, I was able to land face-to-face meetings with clients and close deals.  

Today, smiling is one of the five iconic practices built into the foundation of my sandwich franchise, Which Wich. At my company I say smiling is infectious and I'm happy to say there may not be a cure. After the many strange and fortunate interactions that I’ve had throughout my career (behind the lemonade stand or sandwich counter or on the other end of the telephone line), I can testify that smiling is the contagious, gravitational force that ultimately connects people.   

Related: When the Self-Service Customer Smiles