Girl's Behavior

Why do people have to be unexpectedly nasty?

I was talking to this girl I met on the league. She's in Italy. I am in the US. We would text sometimes, and had some video calls. The last time we spoke I mentioned possibly meeting if I came over to Italy, and she seemed quite keen on it, definitely not disinterested. Soon after I stopped hearing from her, then I discovered she blocked me on WhatsApp. A few months later I posted on her FB asking if this was a mistake and it sure looks bad, asked her to unblock me on there, etc. then she blocks me on Facebook. I literally have NO IDEA what this is over. She could've at least given me an explanation. This is just so disrespectful to me as a person. Plus she acts like she's a serious Catholic and treats me that way. :(
Why do people have to be unexpectedly nasty?
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