A machine has no mind to read; you never know when it’s going to betray you— — Larry Niven

It does not destroy matter, which is reassuring. Rewriting one law of physics is worse than trying to eat one peanut.

A thrint was master over every intelligent beast. This was the Powergiver’s primal decree, made before he made the stars. So said all of the twelve thrintun religions, though they fought insanely over other matters.

Putting a monkey wrench in machinery is often the only way to force somebody to repair, replace, or redesign the machinery. Especially legal or social machinery.