Being a contrarian means disagreeing with people. Even good-faith disagreement is hard, and some people take it harder than others.
One way to disagree without cornering the other person is to spell out what would prove you wrong: “If you can show me X, I’ll accept your argument.”
An entrepreneur pitches an investor:
Entrepreneur: Uber for dog walking is the next unicorn.
Skeptical investor: You’re flipping nuts, guy.
Better: Show me evidence of viral organic growth.
The first answer ends the conversation. The second gives the entrepreneur something to go get.
The exercise is good for you, too. It forces you to steelman the other side and check your own bias. I have knee-jerk reactions to new ideas, especially ones that compete with what I already believe. When I run the exercise, it often proves me wrong.
Being wrong is good. I’m rarely trying to win the argument; I’m trying to find the right way to reach a goal with limited resources.
Take your counterparty’s argument, turn it into a testable hypothesis, and run the test. Now you are both scientists, not lawyers.