I find it honestly surprising that I see it so much on HN. You have a group of people who largely identify themselves as being rational, objective, intelligent people - datascientists, engineers, etc. - who stereotypically I would think to be naturally sceptical and want to examine evidence closely.
But it's absolutely true, the minute some scientific study is posted there are 50 people writing comments that they believe it because yesterday something similar happened to their aunt etc. It's something I've never quite figured out.
It's because HN users aren't really that intelligent; they just give off that impression instead. We're all mostly normal people here, and act like normal people. This isn't some special club of 1000x geniuses.
Case studies can be very enlightening but there are also problems. Stories may be made up or misremembered. There is also a selection bias in which stories get told and which don't.
The big benefit I think is that people are... well people. If you do the same thing to an atom it will respond in the same way, while people may respond differently depending on any number of factors.
Appetite is known to be heavily entangled with psychology. People eat to celebrate. They eat to celebrate or because they are sad, because they are tired, because they are stressed out, because they are bored or maybe because they passed a bakery.
Case studies can help us understand how all these things interrelate and how to design studies that avoid pitfalls.
My favourite version of this is when a scientific study comes out and you get lots of posts from people saying, effectively, I disagree with science based on my feelings. The difference between anti-vaxxers or creationists and the average HN poster isn't as big as many pretend it is, I think.
But it's absolutely true, the minute some scientific study is posted there are 50 people writing comments that they believe it because yesterday something similar happened to their aunt etc. It's something I've never quite figured out.