Ok, I gotta share a bear story, sorry can't help myself.
It was early Nov. around 10 years ago and we had about 4 inches of fresh snow on the ground. I was walking in for my evening sit with my huge Summit climber on my back, pistol in the right pocket of my turkey vest and my phone in my right hand pants pocket under two layers of coveralls.
As I came through a beech thicket I came face to face with big, big boar. I honestly think we saw each other at exactly the same time. We were no more than 15 yds apart facing each other. He stood up on his back legs and eyed me up while I stood there very still not want to spook him thinking "Wow this is really cool". After what seemed like an eternity but was in reality probably 15 seconds he dropped down and started to wander off angling away from me. I took this opportunity to start digging into my layers trying to get my phone out so I could get pictures. While I unsuccessfully dug for my phone the bear would stroll about 10 paces, stop and look back at me for about an equal amount of time. No panic on either of our parts just interest.
After he stopped for the third time I started to think maybe I was digging for the wrong thing and should be looking to get the pistol out. You never know, he could be considering one last hot meal before his winter's nap. Funny how your mind works sometimes.
Realistically, at the range we were apart if he'd had bad intent there wasn't a darn thing I was going to do about it anyway. Luckily, after that last time he paused he broke into a trot and went over a ridge heading away from me.
I have to think that he wasn't exactly sure what I was given the funky silhouette I was casting with that tree stand on my back but I went away from the encounter thinking "What a great experience!"
EDIT: I guess the moral of this story in light of the OP's original post, and any of my other bears stories, is that when you happen across a black bear in the woods the best defense is to not let your emotions take over. Stand your ground, act nonchalant (or big and tough if that doesn't work) and hope the bear just decides you're not worth his time. Running will likely initiate a chase response. The reality is that these things are so quick that if you're within 30 yds you're not going to have time to do anything but duck anyway.