Keeping cool
A lot of people are very bad at managing their own emotions and do not know how to behave with others in public. This can be especially true when they let their emotions get the best of them in a heated discussion and raise their voice, escalating an entire situation unnecessarily.
Do not be the person that does not know when to keep it calm and collected and try to recognize when you are about to lose your cool. If you know when that moment arrives and you manage to control it and stay collected, you could save a relationship and move forward without any silly drama.