What is this guy trying to do?

I have a German friend, he had a date today and I was there by coincidence (lie), then his date stood him up and said "I have important things to do" and he was very upset and so on, we walked together in the park, but he never looked at my face, he was very cold, then a man called me a f*****, then my friend got angry, he was already a big muscular thing, he knocked the man down, what is this man trying to do?
What is this guy trying to do?
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