Examples of a dog refusing to come to your aid in a dangerous situation?

I’m looking for situations where you were attacked or threatened by a stranger (humans are mostly what I’m interested in hearing about, but dogs, wild animals, etc. would be OK too) and your trusty companion cowered behind you, licked your antagonist, or was otherwise useless. I would have asked this question in the other thread but I was afraid it would get lost.

I was walking our dog and ended up chasing a purse snatcher. Someone running usually gets a dog’s chase instinct to kick in, and it did! But my dog was chasing me, not the thief, and was trying to bite my shoes. So I didn’t catch the guy, but he got scared and threw the purse on the ground, so the lady got her stuff back.

ETA: The weird thing is, I go jogging with my dog regularly and he never tries to trip me up then.

^^ That is a hilarious visual: both of you in hot pursuit - but of different people.

That reminds me of a similar occurrence that repeated itself several times with my father’s dog, many years ago. Isis was the greatest dog I have ever known. She was a shepherd-doberman cross and was the sweetest, most sensitive dog you can imagine – loved to be petted. She was intelligent and disciplined and would wait for long periods of time without a leash in the city if she was told to stay.

She did seem, however, to have one odd quirk that surfaced sometimes. She lived with my dad who lived alone at the time. Sometimes my brother and I would come to visit and every so often some wrestling/roughhousing would erupt between my brother, myself, and my dad. As the roughhousing escalated (imagine someone being pinned on the floor while the the other two piled on) she would get more and more agitated and start to bark and growl while jumping in and out of the fray, as if not sure what to do. Inevitably though, she would settle on going after my Dad, much to our delight and his shock (each time) and disappointment, grabbing onto his boot or ankle and giving it a good shake.

I always wondered what exactly was going on in her head. Was she just playing? Was she confused about who to protect and choosing us over him (possible, since we had grown up with her)? Had she been secretly planning a revolt for many years and just awaiting the right moment? And, most of all, what would happen if it had been actual strangers attacking my father?