Ask HN: What is your favorite question to ask in job interviews?
Can be assessing competence or team fit or something else, just curious what people ask. It might also be helpful to specify the discipline.
But two questions that I nearly always ask are: tell me about a project you did (personal or professional) that you found very exciting, with a followup question of "what about it got you excited?"; and tell me about a project you did (personal or professional) that went sideways. This one often has a followup question of "how did you deal with it?"
Neither question has a right or wrong answer. Well, I fib a little. A wrong answer to the "what went sideways" question is "I can't think of one". The only way that can actually be true is if the candidate is very inexperienced.