It does depend. If I am at home and it is a small amount, then no. if I am in the store, or close by, then yes.

With store clerks, I believe in a bit of Karma. If I let an extra buck slide into my pocket, sooner or later I will lose it again, and it will be on the week that I need that dollar for gas or something. I also tend to shop at the same local places, and since I do things like this, I am a valued customer. There have been times where I am a dollar short on my groceries, only to have the manager decide my bananas were free. When i don't have the extra change to get my kiddo an ice cream or lollipop, the clerk pulls one from behind the counter. You know that Indian store owner who is always rude and on the phone, rushing you out of the store? He gets off his phone when I come in.

I try to live my life this way, because of the small effects it has. All those little things don't add up to much, but when you have a rough day, a sinple smile from the gas station clerk, or a joke from the grocery girl can make it all better.

Oh, and the bank thing? If your buddy had not returned it.. it woulda been jailtime. Not correcting somebody when they give you the wrong change is theft by taking. At a bank.. they have this sort of thing on high resolution video, just in case.