With all due respect, that works in some cases. Can’t tell you how many times I’ve seen dogs act as if they’d warm up, only to have them snap at me.
Dogs like to sniff you to check you out. When a dog seems agreeable, I’ll stick my hand out and let them sniff, rather than go for the immediate contact by rubbing them.
Sometimes they’ll nose your hand and you can then advance to rubbing. Other times they’ll sniff then snap.
You can never really tell about dogs.
What I was a kid, our friends had a Dachshund. That dog never warmed up to my brother or I. It would act friendly for a few moments, you’d be rubbing it, then out of the blue go postal. I’ve never seen a dog like that before or since.
So wigglies, don’t always mean a green light.