Petty people like to have their little fiefdoms. You see this with college professors who want to set rules for "their" classroom, or "their" office, and who chafe at the notion that these things do not actually belong to them, but are just the places where they do their jobs.
This also expands well beyond physical spaces. Petty people will try to exert control in any way they can to make themselves feel more important. For example, a mid-level clerk might withhold approvals on something unnecessarily and then act like they are doing you a favor when they finally do their job. These petty tyrants are everywhere.
