The Earned Income Tax Credit.
I bet most here know exactly what it is.
Something like half of income tax filers pay no federal income tax. BUT they pay that pesky SS and Medicare. When they turn 65 or 67 or whatever the govt will do some math and see if they will get a bigger check based on income, or based on disability. Their automatic disability is being over 65. Many lower income folks will get more from SSI. There is a means test but they typically have not a pot to piss in. So to the liberal mind their SS paid in was "wasted" because it gained them nothing.
SO using the EITC we contrive a way to return it to them every year.
Now it DID help balance the budget some in the big picture when they and their employer paid in 12% of their income...but fuck that.
I bet 99% of posters here already knew that.