My mother taught me to say, "Thank you", and this habit has served me well. People like to know they are appreciated. They like the acknowledgement of a positive response from those they help.
What you don't say may say more about you than what you do say. I have had the unpleasant experience of walking through the sales floor area of a department store and no one acknowledges that I am there. In fact they seem disturbed and unhappy that they are there. Oh, how much a nice smile and a, "Thank you for coming in", would have made me feel happy and appreciated. I might even have bought something if I had been engaged by anyone.
Engage the people around you both familiar and the stranger. You will feel better for it and maybe even create more business. And those you engage will certainly have a favorable impression of you.
Thank you for reading my Jim Click Business Preferred blog. I appreciate you.