Quick answer
The appetite comes first and the treatment of people follows. The verse traces a line from what a man wants to who gets hurt.
Read both lines
"Soul" is nephesh, this book's word for a living person rather than for an immortal part of one, settled in the catalog at 12:10 where it belongs to a farm animal. So the first line describes a whole person oriented toward harm, an appetite rather than an act. Then the second line makes the cost specific and local. Not society, not the nation, but the neighbor, the man next door, who finds no favor and cannot say why. That is the verse's real observation: a disposition aimed at evil in general lands on whoever happens to be nearest, and the person absorbing it is rarely the intended target of anything.
Related: Proverbs 12:10 · Proverbs 4:16 · Proverbs 16:29 · Proverbs 21:26
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.