My biggest source? Thinking about how women I knew would screw/ blow EVERYONE but me. I'm not being paranoid or using hyperbole. This was back in HS, which was years ago, but examples like this are always timely.
You know the type; she pitied me, told me that I was her "best friend". But this was Dictionary Friendzoning. She had a "real" circle of friends and fucktoys, whereas I was just some guy she emailed once a month, if that. I would call out her BS and stop talking to her for awhile. She took offense and called me "ungrateful" for her token efforts, and since I was lacking confidence, I would always apologize and try to restart things. They never "started" in the first place though.
I should have just said "No, you pity me, and I know what you do with the other guys. Whore." Women like her are the cause behind shootings, either at the time or many years later.