Passage 3 (excerpt from an open letter by a city's outgoing public-works director, published in a local paper).
Friends — and even adversaries — I leave this office at the end of the month after eleven years. I want to say one thing before I go. The work we do is invisible. It is invisible when it works, which is most of the time. The water comes on. The street gets plowed. The drain stops flooding. No one writes a thank-you note. And then occasionally — say, one winter morning every three or four years — something fails. A pipe bursts in a neighborhood and the calls flood the office, and the question is always the same: how could we have let this happen? My request to the city, after eleven years of answering that question, is this: be a little quicker to credit the boring days. The people in this office will keep the city running with or without your praise. But we will keep it running longer, and with sharper minds, if you remember that invisibility is the most reliable evidence that the system is working.
Based on Passage 3, why does the writer specifically address 'Friends — and even adversaries'?