In all honesty, your experience with a bear on the trail really depends on how much experience that bear has had with a human.
In most states where hunting was allowed, bears will run from humans on sight. My first 2 sightings were such as this.
In the Shenandoahs, they equivilate people with food, and can be more agressive. I know of 2 or 3 people that were mock-charged in the Shenandoahs, cub or no cub.
In New Jersey, hunting bears just started up this past season, so bears do not think of humans as harmful to them. I ran across several bears here that did absolutely nothing when I yelled at them, jumped up and down, made all kinds of noise, and tried to be intimidating. I eventually had to just wait until they decided to amble on.
In New York, a huge bear started following behind me on the trail, as I was singing, clacking my poles, and making noise. The bear only stopped following me when another hiker, not far behind me, yelled at the bear. It then turned around and started walking toward him - he hid, the bear sat down in the middle of the trail, looking and sniffing around for both of us, then eventually walked off.
Some bear encounters will greatly differ from others, so this is why it is always best to be prepared with a secondary defense, such as a long hiking pole to tag his nose with (bears are very sensitive in the nose, and a whack on the nose WILL almost guarantee his retreat), or some kind of pepper spray, which also hits them in their sensitive zone.
Good luck!
bearbait