One seems to be culture.

For instance, I was caught between a knife fight on a train, because in one hood some of the culture is it's unacceptable to play another culture's music too loud. A Hispanic guy was playing hispanic music quite loud on the train, as soon as it entered a black neighborhood a black guy informed him it was "his hood" and asked him to stop, which then escalated to both pulling out knives.

I have now learned there are certain socio-economic enclaves where culture has dictated that I must not play my music too loud or I will be stabbed to death.

In London? Where was this?

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