Sure: A couple of years ago I joined a company doing outsourced system administration. Then it was suggested I should take care of a new client: a manufacturer of weapons with a quite shady reputation.
There were already other issues I had noticed. But this was the red flag for me and I left after four weeks.
My then team lead was pissed and complained I should have told beforehand that I don’t want to go down that route. But it never occured to me before that to compile a blacklist of things I won’t do. And I had been in business for more than 20 years when that happened.