Did you ever quit a job or refuse to go along with something because it was unethical?

In another thread a couple of people said they would do something as part of the job that went against their sense of ethics. I don’t mean anything illegal but something that didn’t seem right. The reasoning is they had to support a family.

I can see this is a choice that some attorneys have to make when they represent a client who is guilty or in the wrong.

I have never been able to make that kind of justification, not because I hold a moral high ground (I can do something selfish or tell a convenient little lie) but doing or saying something that goes against who I am is too difficult. Have you faced such a dilemma?