Rationalize all you want, it's still theft. Be it a dollar or a hundred dollars. Am I guilty, sure, at times, but I also know it is wrong and I don't rationalize it, it's wrong. My being inconvenienced, the clerk being busy, the stores machine not working, the clerk being a jerk, all reasons, but it's still theft!
Now, how about you leave $10 a tip on your credit card. Two days later when you look online at your bank statement you see the charge has cleared and the tip was not added. Do you go back and give the waiter $10. It was a $4 tip and I rationalized I would give it to the waiter next time. Never saw the waiter again. Not theft, but I should have made the effort. We all know right from wrong, I like most just don't practice it all the time.
+1 tailgate!
Ever download a song and not paid for it? How about an ebook you got from a friend. Watch a pirated dvd?