I almost always for an Nth party, where N>2. Literally every single election, I’ve been told that I was wasting my vote, that this was the most important election of my life, etc. There is a tremendous amount of social pressure to vote mainstream. I don’t have high hopes of breaking the cartel anytime soon.
I think the pressure mostly comes from the value that if you're in favor of an outcome, you should be in favor of the prerequisite actions to that outcome. If your favored actions are counterproductive to your favored outcome, then it strikes others as irrational.
