Whoah, what happened to my hand? (no content)

[AtticusFinch]

So here I am on the button, and I'm very pleased to hit a set of fours on the flop. But with all those draws out in a small, unraised pot, I opt for a pot-size bet. It's only when the turn falls and I start greedily counting the chips I'll make from my full house with the flush card falling that I realize that I actually hold pocket twos, not fours, and my hand is worth about as much as a snowball to an Eskimo.

In horror I check it down, even (heck, especially) after hitting my flush on the river, only to find that my opponent had K5o, had called my pot-sized bet with a gutshot, and my pocket twos were good all along.

Ain't this a great game?

P.S.: Think I should bet the river?

Dealer: Hand #77369298
Dealer: jazzmaster posts the small blind of 20
Dealer: AtticusFinch posts the big blind of 40
Dealer: You have been dealt [2c 2d]
Dealer: kobun916 folds
Dealer: Rao3151 folds
Dealer: diceflea folds
Dealer: berkmanmvp folds
Dealer: Canterburykid folds
Dealer: wizzz calls 40
Dealer: jazzmaster calls 20
Dealer: AtticusFinch checks
Dealer: The flop is [4d 8d 7c]
Dealer: jazzmaster checks
Dealer: AtticusFinch bets 120
Dealer: wizzz calls 120
Dealer: jazzmaster folds
Dealer: The turn is [7d]
Dealer: AtticusFinch checks
Dealer: wizzz checks
Dealer: The river is [Ad]
Dealer: AtticusFinch checks
Dealer: wizzz checks
Dealer: AtticusFinch shows a flush, Ace high
Dealer: wizzz mucks
Dealer: AtticusFinch wins the pot (360) with a flush, Ace high