Bear spray is very effective. I carry it in the woods all the time. I never had to use it, but I've had it out and ready a time or two. Once while on a trail a found myself just 10 feet from a mama bear and two small cubs. Mama eyed me as she cautiously stepped around me while sizing up the situation. I froze and made no threatening or sudden moves. After a couple of minutes, mama rounded up her cubs and left. That was in Montana where over the years, I had faced off several bears on the trail, all that turned and bolted away as soon as they recognized what I was. Some of those were before bear spray had been available, and I was unarmed.
So years later I moved to rural Virginia. I quit carrying bear spray, because well.... it's Virginia. Don't ask me to explain the logic in that reasoning. Somehow, I just didn't think it was necessary. So two years ago, I'm walking a trail system made by mountain bikers in a local county park of all places. But it's a big park, maybe just short of a square mile, and I'm a mile up the trail and was charged by a bear. It came running at me, and I'm standing there waving my arms and shouting at it. It stopped and looked at me as if it were processing information, and then started its charge again while I continued waving my arms and shouting. It stopped a few yards away and processed the information again, and then turned around and ran up the trail and into the woods.
I didn't finish that hike, I turned around, got back to my truck, and then I drove 40 miles to the nearest sporting goods store and bought a canister of bear spray, which I've always carried with me since then.