Good poker players are code breakers. Reading this particular situation is fairly easy. A more difficult thing is to correctly conclude how likely the flush-drawing player is to bluff should he miss his draw. Reading the fellow for a bluff after he does bluff, that's basic, good poker. In football, anticipation is critical.
Defensive backs live to anticipate quarterbacks and receivers.
They love correctly reading a situation, and making the moves necessary to make an interception before the ball is even thrown. More importantly, sometimes they must make their move before the ball is thrown, or they won't have the time to make the interception. Baseball outfielders do this too. Poker is often similar. We make money by anticipating our opponent's actions.