That's the sound that most of us are used to when we buy things. I've blogged on this before and there have been numerous collegiate studies done as well on the impact of our spending habits with credit cards vs cash. Well here's a real world one in case you don't like studies.
http://finance.yahoo.com/news/spent-2-weeks-using-cash-150000553.html
If you need to change your spending habits dramatically, go to the all cash diet. I makes you feel the pain. No pain, no gain!