I could have bubble gum only on Saturdays. I loved gum as a kid, but Mom didn't want me to have excess of anything. She wanted to teach me to stay within a limit.

So she'd buy gum for me every Monday, and keep it on my table. I wasn't allowed to touch it. But every Saturday I could have one. And if I was exceptionally good, I could even have two, at most. It not only taught me self control, but also taught me honesty.