Interviews are a source of anxiety for most job-seekers.
From being late to a clammy handshake, there is plenty that can go wrong in those precious few minutes. But it is the thought of being stumped by an unexpected question that keeps even the most experienced professionals up at night.
Now job site Glassdoor has pulled together a list of the 20 toughest interview questions candidates faced over the last year - and the companies where they were asked. Microsoft, Tesla and American Express are among the global giants that left future employees squirming in their seats.
However experts believe such head-scratchers are designed to reveal something about the candidate and don't always have a 'correct' answer. As David Whitby, of Glassdoor, explained: 'It not necessarily about getting the right answer, more how you cope under pressure.'
Here, FEMAIL reveals the top 20 fiendishly tricky questions - and offers an expert opinion on the best possible answer for each...
1 i don't know
2 many such as dwarf planet Pluto and Eris