When you're taking a walk around the block, your body is
mostly on autopilot — you don't have to consciously think about alternating which leg you step with or which muscles it takes to lift a foot and put it back down.
While mandatory spending — mostly entitlements and
mostly on autopilot — remains the largest driver of federal spending and a cause for ongoing fiscal concern, the relative political strength and prominence of mandatory programs made discretionary spending the easier target when it came time to cut.