I'm glad that when I was younger my family fed me with enough candies, So i would never exited with random free candies. I just take it, and say thanks. Since denied an offer is impolite. Plus you don't want overly excited over a random candy, and regret later. (E.g. Someone might kidnap using the candy tactic. Or your candy might be a drug). The sweetness of the candy doesn't last forever, you need some like your family to supply you with enough dose of sweetness, without demand something in return. How would we found the sincere candy supplier? My tip, situational and textuality of the candy.