Why would someone be so rude?

So I connected with this girl, who seemed okay. Super friendly initially, however when I got to chatting with her, I guess I sounded a bit sad/depressed, but nothing too extreme.

She randomly cut in and said she had to finish some of her work, I thought it was rude, but gave her the benefit of the doubt.

Today I noticed I had put up a story which she viewed, and unfollowed me.

I was like what the hell lol. I of course unfollowed/blocked her, but it makes me wonder how people can be so rude, almost for the sake of being rude.

Why would someone be so rude?
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