-Raises good or bad flags about this potential boss and their leadership values & style. Good: they highlight ownership, learning, creativity, and anything else you wish your boss would see in you. Bad: they highlight the employee is loyal, works hard, is highly productive (this one isn't bad by itself, just bad when it's the top or only thing called out). -Establishes that you care about leadership styles, have confidence, and aspire to be the best yourself. It's subtle self promotion.
Regarding bad fits, I could go on about this all day long, but the two obvious ones I'll offer are this:
1) Assuming you're applying for a software engineering position, if they only ever ask you programming-related questions and don't try to gauge things like professionalism, hobbies, communication skills, how you deal under stress, etc, then they're missing the point. (Being able to program is the MINIMUM requirement for the job, after all.)
2) If the interview feels like an interrogation and not a conversation, that's bad. If they spend the entire interview asking questions and then give only enough time for 1-2 questions of your own, they wasted a lot of your time. Interviews go both ways: it's an opportunity for you to learn about them just as much as it's an opportunity for them to learn about you. You should spend half your time asking your own questions, imo.
These aren't deal-breakers, of course, but they're red flags. Enough red flags and you won't be a good fit.
Anyway, good luck.
When I get to that final stage of the interview what I'm really asking a candidate is "Can you tell me something, anything really, that will indicate to me that you are in fact a human being and not a cyborg?"
At university, I once interviewed for an undergrad research position in a particle physics facility. I had noticed, among the towers of papers on the investigator's desk, a single volume of Man Ray photographs. Curiosity got the better of me and I eventually remarked upon its incongruity. Which led to us bonding over a shared love of Surrealism as I travelled through Madrid the summer before and caught a rare exhibit of Salvador Dali's manifestos and other political works. Despite the repartee, that plum position was bestowed upon a more worthy acolyte. But the personal connection was such that he recommended me to another lab, which led to research for a thesis and so on.
And I still remember that interview as a kind of gold standard whenever I interview people. So do not be afraid to stand out. And let whatever it is that makes you unique shine through. Good luck!
I started asking this question because I actually wanted to know the answer. I discovered a side effect: the interviewer would almost always switch to trying to sell me on the company which tended to change the dynamic.