Why do people do negative things to me for no reason?

Like I feel nowadays everyone at every moment is a coin flip for what I’ll get from them. Just the other day I found cheese on my car and I had no clue who the person was and never seen him or spoke to him before and he smeared cheese all over it. Is there a reason people do things for what seems like no reason at all?
Why do people do negative things to me for no reason?
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