Maybe it's because we're human.  Perhaps it's a trait that was inherited through generations.  It could also be because we are under massive amounts of stress.  My question is "why do people lie"?  It drives me nuts!

In a pinch for dinner I drove through for fast food for me and my wife. The name of the joint doesn't matter as even though they are all different, the experience is basically the same. For my wife's order, her only request was no lettuce. Simple. So as I ordered I asked for no lettuce then confirmed the order again before going to the window. At the window, after I was handed my bag of cholesterol, I asked again, "No lettuce right?" The response was " Yes sir, I checked it myself" When I got home my wife unwrapped her artery clogger and there it was, leafy and green - friggin lettuce. I can only draw two conclusions from the way the young lady at the window handled herself and her statement- either she has no idea what lettuce is, or she lied. I have to go with the latter. Maybe it was laziness, maybe she was having a bad day, I don't know. All I know is there is no reason to lie about something small like an order at a drive thru. So at some point I will go back to the chain, circle around the building to see if she is manning the mike at the drive thru, pull up and when she asks if she can take my order I will respond "I know you lied about the lettuce, what else are you lying about?" Yup, that should shake her up a bit.