I once had a conversation with professional poker star Annie Duke about the silliness of bans on betting.  She had an interesting definition of a game of luck vs. a game of skill.

While a lottery is clearly all luck, poker is skill (both people and math skills) and probability, with enough randomness that in any single game a skilled player can lose to a lucky novice.  What about betting on sports?  What about fantasy football?

Annie’s distinction between a game of luck and a game of skill was simple: if you can lose on purpose, it’s a game of skill.

Brilliant really.  If it’s all luck, you can’t control whether you win or lose.  You can’t purposely pick the wrong lottery number.  You can sort of kind of purposely bet on a horrible team, but it’s really out of your hands to ensure a loss.  You can’t 100% guarantee a loss on purpose, so it’s still a game of luck.  Fantasy football is an interesting hybrid, because like sports betting, the game play is out of your hands, but you can purposefully pack your roster with injured players and ensure defeat.

I don’t know why that definition stuck with me, but it always feels like there’s some wisdom in it.