My own experience with black bears is here in the PNW, where they are still very human averse and they run away when they see me. But that doesn't mean to me that black bears are timid and harmless, only that Oregon's black bears are pretty reliably timid and harmless.

Bears have a lot of intelligence and personality, which means that individual bears can vary widely. They also spend up to two years with their mothers, learning the ropes, which means that bear populations can develop different cultures over a period of decades. The bear culture in the Sierras in very different than in the Oregon Cascades. So, if someone says the black bears in the Upper Peninsula are considered dangerous, I'm not inclined to contradict them. It could be a local thing.

The only constant with bears that I know of is that they are always interested in food, 24 hours a day, no matter how much they've already had to eat.