WARNING: This post contains spoilers about the existence of Santa Claus. Read further at your own risk.
Here’s the way it’s supposed to work: For a while, your parents (and lots of other folks) deceive you into thinking Santa Claus exists, and give you lots of benefits (presents) for believing.
Then, eventually, you find out that Santa doesn’t exist, and that your parents (and lots of other folks) are deceiving you, but you want the presents to keep coming, so you return the favor — deceiving them into thinking you still believe.
This is kind of the key phase here — realizing something’s bogus, but playing along because you realize there’s something to be gained by helping prop up a fictional notion. And then, for some period, everybody’s lying to everybody — your parents etc. by telling you Santa exists, and you by telling them you believe them.
And eventually, somewhat organically, there’s a shift in which you and your parents both tacitly (or openly) recognize that nobody’s fooling anybody anymore, and you both begin working on deceiving the younger kids who are still buying into the myth (or pretending to).
The lesson is, there are some fictions that are convenient to maintain for various reasons, and that a transition from ignorance to knowledge isn’t necessarily a transition from deception to honesty. Truth is good and noble and nice and all that, but sometimes a little shared deception (or shared agreement to avoid certain truths) can go a long way toward helping people get along with each other.
(cartoon via Savage Chickens)