The US economy depends on the production and trade of useless and harmful products. Farmers are paid to grow unhealthy food for you to eat. Advertisers are paid to fool you into eating it. Dieticians and doctors are paid to repair the damage it causes. It all goes around in a circle of money like the sneetches between the star-on and star-off machines:
http://www.sundriesshack.com/wp-content/uploads/2011/10/Sneetches-Machine1.jpg
It is almost entirely automated so effort has nothing to do with it. You should be grateful that lazy Walmart employees will have money to spend on whatever your own useless contribution is.