The boy/girl who cried wolf.
I have always believed honesty is the best policy. It's really common sense. It is just too much trouble having to come up with one lie after another to cover up your previous fib. I will be honest now, I am not perfect. Sometimes I stretch the truth, sometimes for convenience, I gloss things over to save myself an explanation, sometimes I tell a tall story as a joke or in order to be tricky, but I try as much as possible, in the the things that matter, to be truthful.
If you have cried wolf too many times, no one's gonna take you seriously anymore. And that's a real tragedy.