When I was eight years old I found a twenty dollar bill on the school bus. Even though my friends told me to keep it I turned it in to the bus driver.
She told me that if no one claimed it within a week I would get to keep it. I asked her every day if anyone claimed it. After a week the money was mine and since then I took that as a universal test that being honest was the right thing to do.
This of course did not always work in my favor (speeding tickets for example)and although I never lied to my parents I did leave out quite a few possiblly important details about where I was and who I was with.
Also, April Fool's Day type of lying doesn't count.
Occasionally, there is a lying or strong bending of the truth emergency. In these rare instances I cross my fingers .