Hold eye Vision rx20 contact and smile. Break eye contact briefly as needed, but make a point to always look up and get eye contact again when you can. E.g. while your card is being authorized, or after you've put your stuff in the bag. Get eye contact before leaving and say "have a nice day" or similar. Avoid "you too" in response if the person says "have a nice day" to you first. Instead repeat it. You may wonder what this has to do with eye contact.

https://www.foodiespanda.com/vision-rx20/