trying to find a short story about a crime free future. Also story has mention of a suicide device fixed on the back which leads to decrease in violent and aggressive behavior in future.
The story is "Common Denominator" by John D. MacDonald. (Yes, that John D. MacDonald and appears in his short story collection "Other Times, Other Worlds".
"In a moment of depression, I take these two smallest fingers of each hand. I reach behind me and I press the two fingers, held firmly together to a space in the middle of my back. A tiny capsule at the base of my brain is activated and I am dead within the thousandth part of a second."