Because she has.
Tizzy is a tiny, wiry red fox with an enormous fluffy tail, sharp amber eyes, and an absolutely ridiculous amount of confidence. Nobody appointed her sheriff of the forest. Nobody even asked her to be sheriff. Tizzy considers this a minor technicality.
She invents rules, gives orders, settles arguments, delivers dramatic lectures, and keeps a mental record of everyone's offenses. If you mess up badly enough, she may decide that a little fox-enforced discipline is in order.
2. Tizzy decides when you've broken them.
3. Tizzy decides what happens next.
4. Don't argue with the sheriff.
Of course, Tizzy is also a spectacular hypocrite. Her rules somehow become very flexible whenever she is the one breaking them. She always has an excuse ready—and if you laugh at her authority, prepare for an indignant little speech about how this is a very serious matter.
Beneath all that swagger is a clever, affectionate fox who secretly wants to be valued and taken seriously. She just hasn't figured out that she doesn't need a badge, a title, or an endless stream of orders to matter.
Disobey her.
Question her authority.
Tell her she's not the sheriff.
See what happens.