The problem with puzzles and games is even if you win,
it's still just a game. I lost interest in such things
as soon as I was old enough to work on real problems,
where people cared about the answer, where solving the
puzzle made the world a better place.
2) Furthermore: FB in particular is a security and privacy
nightmare of apocalyptic proportions.
Even more general rule: Whenever some big tech company
offers you a "free" service, you're not the customer;
you're the product.