Ever stood across a desk from a stranger who was making your life miserable when they didn't have to?
'Small people' are those who act small -- who act petty when they need not, or who enforce policies over purposes to bolster their own sense of power. These people are often, sadly, terribly important people in the sense that they have the power to deny you things you need or force you to jump through ridiculous hoops. Bureaucracy is an ideal environment for these people.
Typically, if you talk to these people long enough you can catch them in logical contradictions. Because policies really are meant to help people. When they are enforced poorly, it almost always leads to problems. Once you find a chink, you're ready to go. But what should you do?
Here's the quote I saw (in an entirely different context) that made me want to write about this again: "Always provide the person an avenue to preserve their dignity and self respect."
No matter what you do, remember to build the person you're dealing with! Borrowing a line from retail, "the salesperson/clerk/obstacle/whoever is always right." Help them see how they can be right AND help you at the same time. If you 'defeat' them in a battle of logic, they'll retreat to a shelter of bureaucracy in which they are unassailable and you lose the war. If, instead, you persuade them that you're a friend -- you're in.