Why men sense sexual interest when there is none and miss sexual interest when there is

The 

Sexual Overperception Bias

, explained.

What is Sexual Overperception Bias?

Sexual overperception bias is the tendency for males to mistakenly perceive interest more often than mistakenly not perceiving interest. Due to female’s capacity for reproduction being limited by time, missing a sexual opportunity has a lower cost than it does for a male, with his unlimited reproductive abilities.

Description

Individuals of both sexes are not always correct in sensing sexual interest from the opposite sex. These incorrect perceptions occur in the form of sensing interest when there is none, and not sensing interest when it does exist. This tendency does not exist in females. One likely explanation for this is the difference in evolutionary risk/reward calculations. Of males, those who rate themselves as having higher value as a mate were more likely to false perceive interest. A likely explanation of this observation is that these males with higher sexual value have learned through experience to have high expectations, and adjust their perceptions accordingly.

Example

For example, a man walks into a bar and smiles at a woman, who smiles back. Despite this signal being minimally predictive of sexual interest, the man, due to millennia of evolutionary training, decides that she likely is interested in him as a sexual partner. He has minimal chances of success, attempts to seduce her anyways.