Three reasons why

A man spends time with you:
1. He wants to/thinks he can have sex with you 
2. You can help him have sex with somebody else
3. You can help him make money/advance professionally

A woman spends time with you:
1. You can help her solve her problems
2. You are exceptionally good in bed
3. She is in love with you


Now we can all chose how to fool ourselves.