I don't growl at people, but I do at things, when they're being unnecessarily annoying.
Like if something rolls off a counter top, or my laces tie themselves in a knot when I'm late, or a pen leaks, or something gets splashed with water that really shouldn't, or I can't open something, or I can't find my keys, or the tape sticks to itself, or a log-in fails to work.
Those of a religious bent would probably argue that I am effectively growling at fate, and therefore the weird and wonderful workings of our Lord. And if that's true, I have only one question:
Why IS everything so f*****g awkward?
Ggggggrrrrrrrrrrrrrrr.