Alesia, I do that too, the spreadsheet.
One thing that really helped me curb spontaneous/instant gratification purchases, was to do research after purchasing something.
Say I was at Marshall's, which is already a thrifty kinda place, and found a Palm coffee carafe for $22. Great deal, right? I bought it. I go home, and look it up on ebay or Craigslist. Find it on eBay, brand new, for $10. Free shipping.
So, on my spreadsheet, I note, in red in the last column, "$12." What's in red is money I bled, by being lazy or not doing enough research/price comparisons before buying.
Non-shop FF purchases are red too.
Red adds up. I have always been really thrifty, so I thought I'd been doing as good as possible, but my first month of tracking expenses using this method, I was really disgusted with myself that I'd "bled" over $700 that month.
------------------------------------------------
Plan the work. Work the plan.