It is unprofessional, it makes other people uncomfortable, and women in particular come off as weak when they do it.
Yet, despite the stigma, many do it. In one survey of 13,000 people, 10 per cent of respondents reported holing up in an office bathroom to let it all out. Another survey of 700 people found that 41 per cent of female respondents and 9 per cent of male respondents admitted to crying at work. I have done it at my desk in an open office space. And while reporting this story, many of my colleagues, men and women alike, admitted to getting emotional at work.