When the return on investment for a date is lower than expected.
Usually accompanied by quantification of the investment balanced against the total return.
I spent 4 weeks listening to her talk about her invalid cat, who's so brave for living despite his injury (it's a damn cat!), and finally, after date 6, she finally lets me boink her and she's a total starfish. I had such bad daters remorse, I considered asking her for the $800 I invested in her as a refund. Total bait and switch.