> "men believe a women is flirting sometimes when they are actually not"

Agreed. I noticed that, too, and I fell for it as well.

I think this is mostly due to two factors:

1. Men often don't develop enough "emotional intelligence", thus they cannot read subtler signals.

2. Men are starved for attention (or compliments): most men seldom receive them (or never). Hence when someone friendly show them kind attention, for them it's an “OMG! moment” and they easily mistaken it.

Besides, women almost never express their interest in a straightforward manner. Therefore, any positive signal from a female could either be “She’s just friendly” or “Maybe she’s flirting” (so they act on the signal to avoid losing a possible opportunity). Since women are never straightforward, men have to guess. And when you guess you’re often wrong.