Cheap shower curtains
The unskilled cost accountant might suggest you outfit your new hotel with cheap shower curtains. After all, if you save $50 a room and have 200 rooms, pretty soon, we're talking real money.
On the other hand, experience will demonstrate that cheap shower curtains let the water out, causing a minor flood, every day, room after room. And they wear out faster. Cheap shower curtains aren't actually cheap.
Productivity pays for itself.
Once you start looking for metaphorical cheap shower curtains, they're everywhere.