Never heard of grown ups using any "rules", and I too could not be bothered to google the subject, but if you are nice to a woman and she is a hard to get, self important bitch who just revels in the attention she gains by you chasing her then tbh most men will give up and be glad that they've had a narrow escape. There is nothing worse than a high maintenance princess. Also if you make an overture to a woman and she doesn't appear interested, you risk being accused of harassing her if you persist, so I think most men prefer to just have a decent, honest woman whose intelligent enough to realise that genuine opportunities for good relationships don't come round that often and who don't play nasty mind games. Nothing wrong with a good flirt, but people need to know where they stand.