I think that sometimes we think of government employees in such a different way than we do employees within the structures of other companies and corporations. One reason is probably due to the fact that many of us have a love/hate or hate/hate relationship with government.
Government agencies work better when the people at the top support them, just like in any other business. The morale boosting provided by First Lady Michelle Obama's visits has got to be good for these folks.

"Every day, you carry out the business of keeping America moving," Mrs. Obama told the agency's employees. "And now that President Obama has signed the Economic Recovery Plan into law, you will also help carry out the business of getting our economy moving again as well."
[snip]
Mrs. Obama said she and the president appreciate the commitment and sacrifice public servants make at their jobs, which is one reason she has decided to visit each agency.
The first lady has also greeted workers at the departments of Education, Interior and Housing and Urban Development. On Thursday, she stopped at the Agriculture Department to hand over a seedling from a magnolia tree on the White House lawn.
"Just know that we value you, that America values you," Mrs. Obama said at Friday's stop. "And together, we can get this country moving again."
source: AP
More photographs of this event at This Week With Barack Obama