What's the best answer for why you left a previous job?

I left my job because of sexual harassment by my boss. How do I answer interview question "Why did you leave your job?"

• My boss said "When I said spreadsheet, _(me)__ thought I said spread your cheeks!" in a sales meeting with 6 other people. His business manager said "That's sexual harassment" amid the general shock.We'd ride in his car to clients and on a few occasions he put his hand on my crotch. He once sat next to me and got up so that his crotch was inches from my face, on purpose. I wanted to keep my job. So I clammed up, didn't respond, because I didn't want to anger him. At a national sales meeting, at a party set up by the company, he ran at me, grabbed me with both his hands on my ass, picked me up and twirled me around. When he put me down, I said I had to leave and he got angry. He was sober. He walked me and a woman colleague to our hotel room, and when I protested again, he said angrily "I'll tell everyone about your small tits!" As time wore on, when I didn't respond to his advances, he singled me out for especially atrocious treatment. I had so much rage it was making me sick, I quit.

• Answer:

  Tell them the truth, there's nothing wrong with admitting why you resigned on your last job.