What the River Really Gives You

The formula

chance to hit on the river
= outs ÷ unseen cards

On the turn you know 6 cards: your 2 and the board's 4. That leaves 46 unseen.

Turn → river

Common draws

Assumes every out wins and only your hand is known.

The truth

A flush draw on the turn hits 19.6%.

80.4%

of rivers miss. That's maths, not bad luck.

Takeaway

Most rivers miss.

So price your draw before you chase it.