Although I have made great effort to avoid doing so, I often have an initial reaction to hide behind a lie as a way of avoiding responsibility or to protect myself. I also have to fight the urge to lie in the effort of making a story more interesting. I would like to say that the truth wins out in these matters, but I can remember instances where it hasn't. Moreso, I worry about the lies I might have told with such conviction that I actually made myself believe in them. I hope they are few, but I doubt they are none.
I regularly find myself in the position of telling minor lies as a way to not crush someone with the truth. Too much truth can often be discouraging, especially to young people who are learning how to do something. Often lies (at the time) of encouragement are what they need to make those lies a later reality.
I also like to lie extravagantly in order to make people laugh. While the words themselves are false, the tone and delivery hold the truth of their falsehood. I tell myself that these do not count as lies since they are so obviously false that the truth behind them is clear.
For my first few years of teaching, I tried to be honest about my tendency towards falsehood. I warned them that I was a compulsive liar: a person who continually feels the urge to lie. This did not go over well with several parents.
However, I am personally more likely to trust a person who is truthful about dishonesty than one who claims to always be truthful. Too often have I see "truthful" people who are blinded by their own deceptions. Entirely too often, I have witnessed people who have used "truth" as a bludgeon against those weaker than them or as a means to achieve a greater dishonesty. It saddens me when I see people use truths to hide or obscure Truth.
For I do believe that there is Truth, and I believe that Truth is glorious.