Study: expressing sadness can increase your ability to "claim value"
1. If the crier is perceived as being in a lower-power position
Whether you're in tears in front of your supervisor or the company's CEO, your chances of leaving a negotiation happy are increased if you're viewed as a lower power.
"A person who perceives you as having lower power and feels concern for you may help you or make more concessions, leading you to gain relatively more," said Shirli Kopelman, one of the researchers and a professor at the Ross School of Business at the University of Michigan.
2. If the recipient expects a future interaction
Crying during a bombed job interview may provide no benefits for you because the interviewer may never see you again.
But if you're negotiating for a raise or extra time off with your current employer, they may be more sympathetic and concede to your request because you will most certainly be in contact again.
3. If the relationship is collaborative
There's a good chance a coworker would show you sympathy simply because they see you on a daily basis. (However, it is also safe to assume they would become very fed up with you if the sobbing became a common occurrence.)