It's much harder to lie than to tell the
truth. You have to
keep up with what you said and who you said it to, you have to strain your mind to come up with something
plausible... Altogether
too much like hard work for my liking.
However, not everybody (including me, at times) is prepared to pay the price for perfect honesty. Or have others pay the price for oneself - after all, is it really worth telling your little sister her prom dress is hideous and wounding her feelings forever just for the sake of your own self-imposed ideals?
I supposed as one grows up one finds a workable compromise in regards to lying to others - unfortunately, very few people ever learn that the absolute worse thing they could ever do is lie to themselves.