What is the most important question to ask in a job interview?

There are no universally good/bad interview questions. The most suitable questions ALWAYS depend on the job you are interviewing candidates for. Before doing any single interview, whoever is in charge of making the final hiring decision should spend time defining what they're looking for. If you don't know what kind of candidates you're looking for, every interview question has about 0 value. After properly defining what is important to succeed in the open job, you should build your question list based on those factors. If the job is about supporting customers, then the best questions will be ones that are useful in evaluating customer focus and relationship-building skills. For jobs that are about building products, creativity and problem-solving might prove to be more important factors. That's why it is quite dangerous to have "favorite" interview questions. Interviewers should always think: what attribute am I evaluating with the question I am about to ask?

My favorite developer question is tell me how the internet works. What happens when I enter the name of the site in the web browser. This is the most open and general question. It allows you to understand how broad the applicant's outlook is :)

Not as quirky as yours but: I recently heard of a great questiona that was asked during the interview that my partner was conducting with someone to join their marketing team (their work would be in demand gen) and the person asked her "What Hubspot plan are you on?" It's a great question because it showed he paid attention to their stack, he knew what he was going to work on, and showed that he understood the differences between plans on his toolkit. I believe that when a candidate does research and asks a tool-specific question (or a metric-specific) it's a great sign.

Can you take a compliment? This is a question I love to ask in an interview. Being a good learner, a good employee, and having a good mentor relationship with your boss is essential in an interview. But the ability to "taking a compliment" is the key to success in any relationship. Very often, a person doesn't know they are good at something. If you compliment them, they will accept it and learn they are good at it. So this is the most important life skill to develop. As for the second part of your question, I will choose a microscope as I am eager to learn about microscopic-level things that are amazingly small but plays an essential role in nature.

"Tell me a time when you broke the rules" or "Tell me a time when you've made a mistake" hate these

Starting from the end - I'd choose telescope. As a perfectionist, I sometimes focus too much on the details of a task or a project. This can lead to spending too much time analyzing specifics of the topic that I work on. Therefore, I put a lot of practice and effort to shred this burden of perfectionism and I started looking for a balance between the general picture and avoiding minor mistakes by giving myself a chance to refocusing on the bigger picture of the project or task. Telescope would be a perfect gift for me then, so I could observe objects from the distance. :) As an employee, it's difficult to say which question is the most important for the employer - I believe it depends on the role and profile of the company. However, I'm always being asked about my motivation to work. This seems to be rather a simple question, however answer does not need to be simple. Each person might have different motivations and it's good to check whether their answer matches the company goals.

Not as funky but I've found "What motivates you?" to shed light on what someone's really looking for in a role. It's helped us really find people who align with our mission long term.