Good and bad are relative. Not just that one and the same action is good for one person and bad for another: not just that these rural families were put onto the electrical grid and the cost of those losing their homes forever because now those homes lie at the bottom of the lake made by the dam which is producing that energy. Not that this electrification was all good or all bad for any one particular person, either: a person displaced by the dam may find it to have been both good and bad for him because he misses his own home, but he thrives in the city to which he has been relocated in a way he doesn't think he ever could have done back home. (Not that he knows for sure.) One thing can be both good and bad for the same person.
To stick with rural families and water: the same unexpected rain which cancels the Sunday baseball game for which Bob had bought tickets and driven his family quite a long way into town, an outing they had been planning for months, and they won't be able to attend the Monday doubleheader with which the team is making up for the rain-out to some its fans, but the same unexpected rain from the same storm might save Bob's parched crops, and allow him to keep his farm and head off the foreclosure, from the sadness of which he had been trying to distract his family with the outing to the city and the Sunday ballgame.
The heedless bicyclist on the sidewalk might knock me down and break my arm. Very bad for me, but it might be that at that moment I had been a very heedless pedestrian, all up in my head, concerned with moral relativity instead of traffic, muttering to myself and gesticulating angrily at theologians who weren't present instead of watching where I was going, and so the heedless cyclist, who knocked me down because I wasn't paying enough attention to jump out of his way, might have been the only thing which prevented me from stepping off of the curb and into the path of a speeding bus which would've killed me. In which case it's very good that the bicyclist knocked me down and broke my arm. Regardless of whether the cyclist or I ever had any idea that the accident which happened had prevented a worse one.
In short, reality is much too complex for concepts such as sin to do it any justice. And that's very plain to see. But wait, saying that it's simple and plain to see may be an oversimplification. It's plain for me to see because I've read authors such a s Nietzsche. Nietzsche made the case for moral relativity in a very sound and convincing manner, and I've been pondering what he wrote for over a decade and a half. During that same decade and a half your attention on the subject of morality may have been held by smug Anglican morons like GK Chesterton and CS Lewis and JRR Tolkien and Francis Spufford, whose minds are as soft and sluggish as their bodies. Because of your misfortune in reading material, it may really be as unreasonable for me to be annpyed with you and think you're a moron because you haven't got a clue about moral relativism as it is for you to smirk at me because I don't understand your inside jokes about Episcopalian clergy and church services and coffee klatsches and golf courses.
Except of course that it's not unreasonable of me inasmuch as I'm speaking of principles applicable to the entire human race and to much more than that, while your frame of reference is a lilly-white WASP-y version of a nerd-filled comic-book store. The socially-crippled comic book guys won't admit that they're afraid to cross the street and talk to those women who have worked over there in those stores for years now, much the same way that you deny that you're afraid even to think about the implications of the speculations of centuries' worth of the intellectual world getting on with it without you. I'm afraid to talk to women, too, but I cross the street and do it anyway. I act in spite of feeling exactly the same anxiety as the comic-book guys, just the same way that contemplating a random universe with no supernatural Beings caring for me terrifies me, but I contemplate it anyway, because a world based on Leviticus and Matthew and so forth makes just as little sense as a universe in which Superman and Spiderman and so forth are real.