Separation anxiety
Genuine panic at being left alone — not boredom, not spite, and not something a dog grows out of on its own.
Also called: separation distress · dog panics when alone · home alone
The distinguishing feature is panic rather than mischief. A bored dog chews a shoe and then sleeps. A panicking dog paces, drools, howls without pausing, scratches at the door it last saw you leave by, and often will not eat anything you leave behind — a dog in real distress does not touch food.
It is also the problem most often misread as revenge, because the damage is by the door and the mess is on the rug. Cameras settle the question in one afternoon: distress starts within minutes of the door closing, long before any decision to "get back at" anyone could form.
Work is built on absences short enough that the dog never actually panics, extended by seconds rather than minutes. It is slow, it is unglamorous, and it is one of the most transformative results in behaviour work when it lands.