Once all parties have voiced their concerns, you should verbally summarise the conflict, defining the key points; this will ensure that you fully understand and appreciate the issues in the dispute and it further demonstrates that you have been paying attention to what has been said.
If a customer get aggressive at the reception, you should isolated him in a different room that not every customer can see it and try to fix the problem.
At work, maybe for the boss to have 2 entrance that if someone want to speak to him not all the colleagues could see this person was crying or something happen for the privacy.