To be honest, often I've discovered that being truthful isn't the worst thing, as there are those in this world that don't believe honesty as it is.
My late stepfather had a running joke, that he just couldn't catch me in a lie. He admired that of me.
As far as limitations with truth, there's ways to be honest and still hold from exposing what needs to be withheld.
I'm in there with the speculative genetic component, ministers, teachers, religious laypersons, etc.

Edit: Fact is stranger than fiction, comes to mind.