In any situation – a work situation, in particular – you're likely to come into contact with unreasonable people. People who, by the very way they thoughtlessly communicate, spark your desire to strike back with equal force.
Putting dysfunctional / unreasonable energy into an interaction is never the answer. You'll only get back more of the same, and the cycle will never end.
In our consulting work, we deal with a lot of "broken" situations and, thus, a fair number of people who put out unproductive energy.
Today, we were presented with a choice to meet crazy energy with crazy energy or to do our best to shift the tone. Of course, we aimed to shift the tone. Firmly communicating that proceeding unproductively is not an option, we always give people a chance to get back on track. With that message, they rarely come back in crazy mode. If they do, we don't play. We kindly release them.
You can't reason with unreasonable people.