I had to go back and read the early posts in this thread. As victor has illustrated so well, it's not an easy answer. Will summarized nicely.
My lying was, yeah, a survival mechanism more related to an abusive household where telling the truth, even in response to an innocuous question, would have disastrous consequences:
"Did you have a good time at your Dad's?"
"Yeah, I had a great time."
"The only reason you like it there is because they spoil you!" (an angry, vicious Mommybitch rant that would then continue for days)
Regarding the CSA, when I told the truth to my high school guidance counselor ("I'm gay"), he used it as information to rape me over nearly a year.
It's taken me dozens of years to get into the conscious habit of telling the truth. It generally remains a conscious choice. Often it's not as difficult as I think, say, in recounting a personal story without embellishment. Other times it difficult, particularly when I feel some part of my survival is at stake. Even as an adult, in situations where I feel I should be able to be candid with "authority" figures, for example, I've often been disappointed, invalidated, or just plain angry that my honesty isn't respected. Therefore, I share a bit at a time, note the response and proceed from there. Simply, there are lots of people with agendas for whom honesty, exercising it or honoring it, is irrelevant.
I have a couple friends and relatives - count 'em on one hand - with whom I can be honest, even when it's hard. Most of the time that's enough. I just did it with a cousin the other day concerning his dead mother's part in estranging me from the family. He'd suspected as much...and then told me one reason I was his favorite cousin was that he could count on my honesty. Then again, we have the advantage of our respective 12-step programs. With some people I just don't care (no emotional investment) and I choose honesty, no embellishments.
Others who have violated my honesty (specifically, my trust) get cut off. Sometimes with explanation. Sometimes without, if it's clear they have no moral compass.
I think what it comes down to is determining who is worthy of my trust.
"The Answer to the Great Question Of Life, the Universe and Everything Is...Forty-two."