Why are so many women so cruel?

For the past year I've been sitting next to a girl at work who has been waging an extremely nasty bullying campaign against me for nothing. Today I had to move chairs to get away from her and I now sit on my own, isolated from the team, looking like a prima donna, while she laughs, all because of her. I sent my sister a card and some flowers when she was ill 10 days ago and I never got a word of thanks even though my mum told me she got them. I went to a cafe and the girl working there gave me a long sit and then tried to short change me and was horrifically rude when I complained. I then went to the supermarket where a girl who I have known from my church for several years walked past me and scowled at me when I smiled. I find so many women are like this and I also think they enjoy it. I never meet any who have manners or who are kind. No wonder so many men are so violent nowadays.