What was your biggest professional failure?

This is a very unpleasant question. It is actually worse than the one on weaknesses. But you of course see the similarity although the latter wants a more specific answer followed by an explanation into the circumstances of the failure. This interview question is quite often mistakenly perceived by the interviewee as illegitimate. A grave mistake and common behavioral pattern of many job applicants is to try and hide failures or mishaps. Job applicants often think the interviewer is trying to set them a trap; this is wrong - the interviewer is trying to get to know you. 

Do you know that the one who has just asked you the question has his/her own professional failures? They may also be grosser than yours. The assumption is that everyone makes mistakes. Naturally, we are not referring to colossal failures then none of us are immune to mishaps. For example, we may make a wrong estimation or fail to meet our goals (this can also happen for objective reasons). Other examples may be like inability to complete a project due to lack of resources or failure to meet a deadline because of overload.

It all depends on why there was failure. Do not cite failures while blaming others because it may be seen like you do not like taking responsibility. Therefore, failure in a specific instance does not necessarily mean you are not a worthy candidate. Failure is part of work, actually certain mishaps are natural and we must not try to conceal them during an interview.

What is your attitude towards your failures? Your attitude towards your failures is paramount to the impression you make. If you treat failure as a learning experience then you will make a positive impression. However, if you feel that failing is just short of a catastrophe then you will come across as stressed out and nervous - a candidate that cannot deal with failure.

In a nutshell, to answer this interview question in the best possible manner, you must answer in an honest and candid manner. Think of a real failure or mishap you had at work that is reasonable. Do not think of outrageous failures. Always cite the ones that can be seen as a learning point. Show how you learned from this mistake and how you improved your ways to avoid such mishaps in the future. Turn the negative experience into a positive one.