Here’s the hand that prompted this line of thinking:
Full Tilt Poker, $3/$6 NL Hold’em Cash Game, 6 Players
LegoPoker Hand History Converter
SB: $704.60
BB: $791
UTG: $1,075.05
MP: $537.70
Hero (CO): $1,817.85
BTN: $731.65
Pre-Flop: T
J dealt to Hero (CO)
2 folds, Hero raises to $21, 2 folds, BB calls $15
Flop: ($45) 6 T
4 (2 Players)
BB checks, Hero bets $36, BB calls $36
Turn: ($117) Q
(2 Players)
BB checks, Hero bets $90, BB calls $90
River: ($297) 5
(2 Players)
BB checks, Hero bets $220, BB calls $220
Results: $737 Pot ($3 Rake)
BB showed T K (a pair of Tens) and WON $734 (+$367 NET)
Hero showed T J (a pair of Tens) and LOST (-$367 NET)
I bet my hand for value on three streets only to learn that I was behind all along. Flop and turn, I think, are very clearly profitable bets, so the only question is how often worse hands will call on the river. In one sense, this bet was a ‘mistake’, since I didn’t have the best hand.
But if you are not occasionally value betting into a better hand, then you are not value betting often enough. To show a profit, a bet in this spot only has to beat more 51% of your opponent’s calling range (discounting the possibility of a check-raise bluff, which is pretty unlikely). So in fact, in a spot like this, you should be getting called by better hands something like 40% of the time.
Let’s suppose that JT beats 60% of my opponent’s calling range and that I am never check-raised. That means that 60% of the time that I bet I win an additional $220 and 40% of the time I lose $220, for an expected value of $44, or nearly 4.4 BB. That’s about how much I make, on average, from playing QQ, which means that failing to bet in this spot costs me as much as open folding QQ pre-flop.
Hopefully you can see how similar analysis would apply to ‘mistakes’ like failed bluffs, failed squeeze plays, calling when you can only beat a bluff, etc. It’s a pretty big mistake to never make these kinds of mistakes.