First, you reason: out of three dice, one will always be the "middle" one, and only one out of three times it will be mine, so my odds are just 1/3 -- I shouldn't play.
After a while, you realize that you forgot about duplicate numbers. About 50% of the time, all three dice will be different, and then you have 1/3 chance of winning. But on the other 50%, you assuredly win, so the game stands 2/3 in your favor.
It's clear that BOTH lines of reasoning cannot be right, if any. Should you play, or shouldn't you?
Note: you can solve this mathemathically, or you can use "lateral thinking"; can you find both ways?