perspective, that's how - say there's a dude standing on the train tracks and there is a train headed straight for him - you might think the guy's a fool and deserves whatever he gets...on the other side of the tracks, another guy looking from the opposite direction can see that the man's foot is shackled to the tracks and grabs his bolt cutters or whatever to get him free - and there you have two people observing the same event in different ways