I live in Maine and there are alot of bear here. I was a lumberjack most of my life, so I have spent many many days in the Maine woods. Black bear generally will not bother you, a sow with young cubs will however.
If a bear hears you, you will generally never get to see it, as they don't generally prefer to be around humans. I have walked right up to a bear, within 5 feet or so, in a dump, my buddy was behind me, about 20 feet or so.
The bear was setting on his hind end, as I got to within 5 feet of him, he got on all 4 legs and started walking to me.
My buddy got scared, and started to turn and run. I hollered at him and told him to stop, and turn back and face the bear, stare him down and back away slowly.
I stared him down and also backed away. My buddy could have excited the bear and got us both hurt. My wife and kids were in the car watching, and his wife and daughter, were also watching from their car.
My intention was to pat the bear, on the head. I wanted to show my kids that they don't have to be scared of the maine black bear. Of course I explained to them, that there are times when you need to be very careful, as mentioned earlier.
A sick bear may bother you, also. In general you do not have to worry about bear. There is always exceptions, so be prepared, and you still should be ok.
Hope This Helps.