The futile act of relentlessly arguing a position to a person or audience, knowing they have already rejected it. Often the goal is not to convince anyone, but to antagonize dissenters, congratulate oneself for excellent arguing, or perhaps to instigate an entertaining or damning reaction.
"Should I even talk to my mom about climate change? Nah... that would be pointless crusading."
The act of angrily tearing down buildings or burning them while running around yelling "DUES VULT" or god wills it and if you encounter anyone who is not screaming with you killing them and yelling "DUES VULT INFIDEL." Also plundering the town.