Truth in Fiction, Fiction in Memoirs, Writerly Responsibility

I took an online class in memoir writing recently, at writing classes.com, and for one of my works, I used a made up quote, cited by fictional character I made up. The character and quote:

"Every man understands the value of self destruction."
Joshua Quane

Almost everyone who commented on the piece said they liked the quote a lot. Was that so wrong to fool my audience? Does the writer have a reponsibility to be truthful? Or, free license to spin whatever illusions he/she wants? Can/should the writer lie as much and as often as he wants, indeed, is this not his job?