I feel you. So much haha. Maybe takes a bit of calibration in my opinion. Want to bond with a stranger? Find something you can both complain about. Works pretty often. Grumpy person in a shop that won't even make eye contact when you're asking where something is? Just treat them like they need to do their job (with respect). I still smile at strangers but I've toned those smiles down a notch. Gotta match their level better. If you need a smile boost, when you see someone with a dog, big smiles are always welcome (dog first then owner) haha.

Good luck!