For the number one spot... "I'm reading an obscure article (which I won't provide) and the author claims P is true. But I think not P. How can P be true when I also assert a factoid from my very narrow sub-field?"

@GeneralAbrial: I don't know... @Scortchi's #2 is pretty good. Reading an obscure article entails some effort plus questioning the article shows a minimal understanding of things. Blunt : "How to analyse this?" probably would score higher...

@Scortchi "rough on new users" - I read Workplace.SE. Compared to them, we are bunnies and fluffy kittens!

(And I fully support a meta thread on this. With one answer per list entry here, let people vote the best to the top. And with explanations why something is bad. Then we can actually point to that list when voting to close.)

I love all these contributions to the Top Ten list. If you want to keep ranking them, I invite you to use decimal numbering, such as 3.5 (midway between third and fourth), etc.

Was I being unreasonable here?

@Kodiologist Interesting case. I would have had the same intuition as you, but not the confidence to express it so strongly.

It's very mysterious to me what would make fitting n unrelated regressions a "major strength of the method", maybe that's a place to ask the poster to elaborate.

It also seems to me that the poster probably does have an XY problem, but I can't be sure.

I would probably recommend structuring the data as you do, and using a multi-level model of some kind. Seems like you know a bit more than me though.