I guess it depends on my mood, and perhaps the setting. Here are two examples:
I forgot some small thing in my grocery cart once and found it when I was putting my bags in after having already paid. I immediately told the guy (the asst. manager) who said to "Go ahead." He said I spend enough money at that store that this one thing wouldn't hurt. So there I paid in full.
A few months ago I was doing a mock draft over on the Football side, and I hit Submit on a pick. About two seconds after hitting the button I realized I should have done something else, and since nobody had been in the thread (it was later at night or something) I redid the pick. Of course, there are people who have picks emailed to them so this was discovered, and some people were pretty pissed. At the moment it seemed like a little thing, but it turned out to be pretty big, and people left the mock because of it.
In the grocery store setting, I would never have intentionally walked out without paying for something. In the mock draft setting, I thought it would be OK to redo a pick I screwed up. Two similar situations, two different results.
Keep wreves in General Talk in 2011!