Stress
You can call yourself a public administrator, but all some people will hear is "bossy pants." Whatever it is you specifically do, most people know that your job is both necessary and largely thankless...hopefully they'll keep that in mind.
Of course, some people will still be jerks. Maybe you caught them on their bad day or for them, every day is bad. No one wants to deal with the housing authority, waste management, or even the U.S. State Department, so don't be surprised if someone occasionally puts on their grumpy pants before talking to you.
Then there are those other people. The ones who think any form of order or civil authority is oppressive tyranny. Yeah, they're the fun ones.
From tax avoiders to corrupt landlords to the elderly woman who is sick of so much diversity in her neighborhood, the fringes of society may become part of your every day. Buck up, soldier, you're the one who chose the career with the word public in it.
Have we mentioned a sense of humor is important? It's a good idea to have one, to be able to laugh every once in a while, because some days you're just going to want to go home and cry.
The second part of this joyous two-fer is the administration part, and that comes with its own set of stresses and struggles. Remember, this job is all about plans and your ability to pull them off.
You may have coordinated all the little parts, gotten the right signatures, and greased the proper elbows only to find a new housing development gets put on hold because an endangered species of salamander has decided to take up residence where it was to be built. As a famous Scot once said, "The best laid plans of squirrels and stuff often end up a pile of haggis on the floor."