I searched for this topic as I thought it's a common one, and was surprised not to get any hits on this forum.
This catch-phrase comes from a popular '90s book. Venus also is the Roman goddess of love and beauty, while Mars is the Roman god of war. I wonder if that was the author's perspective while writing that book.
Anyway, I thought it would be good to discuss common misunderstandings between men and women. One that recently came to mind is that many men think that women dress for them. That's probably common in Malaysia where some men even blame women for causing rape by the way they dress. However, women actually dress for other women. After all, most men wouldn't realize that a woman is wearing new earrings or has a new outfit, while other women observe these changes immediately.
I've made generalizations regarding men's and women's attitudes. Feel free to agree or otherwise :-)