My neighbor played loud music almost every night. We were friendly, and he often helped my family with small things. I didn't have the courage to confront him directly, so I filed an anonymous complaint.
He later came to my house and complained about "some miserable person" in the neighborhood who couldn't tolerate music. I agreed sympathetically while knowing it was me. The music stopped. Our friendship continued. I am apparently both the helpful neighbor and the miserable person.