I could be generously described as a fabulist when talking amongst friends and I definitely just view it as mental practice. Being forced to think on your feet on a regular basis is a great way to improve your public speaking ability, your creativity, and your general knowledge (as you need to learn and retain all kinds of nonsense to come up with some plausible-sounding excuse for whatever absolute bullshit you last said).

That it muddies the waters of "who I really am as a person" is probably true, but that's mostly just an unintended side effect. It's just that my real person is definitely way less entertaining than a well-constructed yarn or joke.