What your interviewer is really trying to do with this question—beyond identifying any major red flags—is to gauge your self-awareness and honesty. So, “I can't meet a deadline to save my life” is not an option—but neither is “Nothing! I'm perfect!” Strike a balance by thinking of something that you struggle with but that you’re working to improve. For example, maybe you’ve never been strong at public speaking, but you've recently volunteered to run meetings to help you be more comfortable when addressing a crowd.
Tip: It’s easy to get hung up on figuring out your single most impressive accomplishment. Instead, think of a few achievements that showcase your work ethic and values. If you can, pick examples that also tie back to the job you’re applying for. The STAR method is a great tool to ensure you highlight not only your role but how you drove business results. 
I am Mario, 25 years old, and I have just finished my Masters in Economy. I enjoy team work, and I am looking for my first job, ideally in a big company. I want to learn, and meet like-minded people in work. In my free time I like to run, read, and meet with friends. I try to have positive outlook of life, and take everything that comes my way as an opportunity to become a better person.

Of course, if you have an issue that is very important to you that could be a deal-breaker (like company culture), you can mention it. Just be prepared for them to take one extreme or the other. For example, maybe you only want to work for companies that buy from vendors in your home country. The hiring manager will let you know if their company does this. And if they don’t, I guess the interview is over.
Nothing says “hire me” better than a track record of achieving amazing results in past jobs, so don't be shy when answering this interview question! A great way to do so is by using the S-T-A-R method: Set up the situation and the task that you were required to complete to provide the interviewer with background context (e.g., “In my last job as a junior analyst, it was my role to manage the invoicing process”), but spend the bulk of your time describing what you actually did (the action) and what you achieved (the result). For example, “In one month, I streamlined the process, which saved my group 10 person-hours each month and reduced errors on invoices by 25%.”
This is a tough question to answer without dipping into platitudes. Try sharing leadership examples instead. Say, "The best way for me to answer that is to give you a few examples of leadership challenges I've faced," and then share situations where you dealt with a problem, motivated a team, worked through a crisis. Explain what you did and that will give the interviewer a great sense of how you lead.
If asked this question, be honest and specific about your future goals, but consider this: A hiring manager wants to know a) if you've set realistic expectations for your career, b) if you have ambition (a.k.a., this interview isn't the first time you're considering the question), and c) if the position aligns with your goals and growth. Your best bet is to think realistically about where this position could take you and answer along those lines. And if the position isn’t necessarily a one-way ticket to your aspirations? It’s OK to say that you’re not quite sure what the future holds, but that you see this experience playing an important role in helping you make that decision.
You won't be asked a hundred questions at a job interview, but it's completely understandable if you feel overwhelmed looking at this list. Just know this: Nobody expects you to have all the answers—that's what the experts at Monster are for. Still have questions about the hiring process? Join Monster today. As a member, you'll get career advice and useful tips sent directly to your inbox. From resume-writing checklists to lists of companies hiring to how to get promoted, Monster will help you plot an awesome career path, one step at a time.