Unforgiven, I'm going to argue with some of that......
Scent is airborne.....the best nose in the world can't smell what is upwind in a decent breeze.........
I know bears have lousy eyesight....I should have stood up to show I was a man long before he got so close to me (my bad).........animals have a fight-or-flight "zone" within which it is very unwise to startle them........
I am convinced he had no idea what was there, and was coming to investigate my flailing arms

.........
I was not that alarmed, obviously, or I would have shot the thing.
I had a more dangerous confrontation in fall with a LARGE bull moose, obviously in rut.........talk about unpredictable! In a heavy rain I got far too close, and he behaved agressively, rolling his antlers at me, lowering them, taking steps towards me......then head back, nostrils flaring.........probably 1600 lbs of testosterone-charged muscle.....antlers looked like a twisted snow plow......wow! I didn't shoot him either

.
I stood my ground and spoke to him........rifle on the shoulder, mind you. If he charged, my plan was to snap off one, and run around the large fir tree on my right

He was probably 10 yards off........and he backed down.
Gotta love the bush. I'm hardly there anymore.......