Businesses are motivated by profit. You push your employees to work hard in order to maximize your owners' (either your or your shareholders') profit-making ability. This leads to incentives for sales teams, team-building promotional activities, quarterly performance reviews, and a highly competitive workspace.
The public sector, on the other hand, has other motivations. Most public services exist to fill a vital need. So long as that need is being "adequately" filled, managers don't push their staffs to work any harder. Overtime is rare, and competition is more for personal fulfillment than to earn any kind of reward-based recognition.
This dichotomy leads to two very different worlds and work ethics. Walk into any clothing store. Within a few minutes, store personnel will greet you and offer to help you find what you're looking for. They'll be ready to answer questions, suggest various products, and many will personally check you out when you're finished shopping. A high level of customer service for a low-paid employee of a "money-grubbing empire."
Walk into a public service building like the DMV. You won't be greeted, you'll have to press a button to take a number (if you can figure out where to get it), then you'll wait patiently for up to an hour to have your number called. You'll be served by one of maybe ten staff members whose mood and temperament reflect their desire to be anywhere but behind a counter helping you. A very low-level of service for an employee paid by the public - paid by you.
So to all of those who would disagree with my characterization of the motivation behind public sector jobs, I invite you to disagree. How do you motivate your staff? What other forms of drive have you seen among staffers in public venues? I'll admit that this reflects just my own personal experience, so I welcome your input.