Why do you care about how your taxpayer dollars are used by government?

Once you pay taxes, its done. How the money is used by government and what it does with it, is really not your business. For example if you go to a grocery store and pay your grocery bill, do yo really care how the store uses your money? Likewise why do you care about government spending? Once the money is paid, its irrelevant how your money is used by the merchant. I think its just stupid to keep looking at how taxes are used