Does anyone understand why some men just can't seem to take "No" for an answer?

I read of two accounts on Fluther, just today, where women were faced with men pressuring them for sex after they’d repeatedly turned the men down.

Most men are good about walking away in disappointment, but there are some men who just keep after the woman and keep after the woman.

Anyone know what their logic is? Do they think we’ll change our mind after the 36th attempt? Do they think we don’t really mean it?