My favorite is Barry Marshall. He thought there was a connection between bacteria and ulcers, which was an unpopular opinion at the time. So he intentionally drank the offending bacteria, got sick as expected, and then people believed him.

More here, including (which I didn’t know until now) cardiac catheterization.

I’m sure better sources exist but https://www.discovermagazine.com/health/these-five-doctors-experimented-on-themselves-and-made-big-breakthroughs

Innovation, perhaps; progress…that’s something else.

I’m gonna try to guess the most likely LLM response to your post, trained on reddit data:

“This.”

How’d I do?

It’s a matter of perspective and use — high density one place means you can have open space somewhere else, for a given amount of land.

I’d much prefer a few large dense housing complexes, surrounded by green space, than suburban sprawl.