Man can I relate to this thread! The lying was hands down the worst side effec of my drinking. As many of the other posters have said also, I am an incredibly honest person with integrity when sober, yet once inebriated, I become a different person entirely. I've told pointless lies and damaging lies, big and small, across a whole spectrum. That sick feeling in the pit of my stomach when the lies I've told when under the influence flood back to me is what motivates me to push forward with my sober journey and to shun the AV.
No idea why I do this, I would never behave that way sober. I'm sure it is the interaction of alcohol at play with my deeper insecurities. That's the problem with alcohol - you abuse it because the AV promises it will help to soothe your pain and your damaging thoughts or inner worries, yet in reality it manipulates and exacerbates them.
Best of luck.