The problem with telling a seemingly innocuous white lie is they propel a rapid-fire domino effect until you inevitably are caught in a full-on web of lies. If you fess up, then you're caught in a pit of embarrassment for lying in the first place. Basically, it's a lose-lose situation that many of us how found ourselves in at one point or another.
Obviously, there are different tiers of lying. Knowingly deceiving someone about your identity or intent falls under a very different category than unthinkingly lying about what kind of breakfast meat you prefer. In most cases, the dumber the lie is, the funnier the circumstances are thereafter.