The problem is that pure rationality leads into abyss. There might be a rational decision not to punch people directly into face but a purely rational psychopa

The problem is that pure rationality leads into abyss. There might be a rational decision not to punch people directly into face but a purely rational psychopath can choose many other profitable avenues that are disastrous to society at large "in the long run" (fentanyl, global warming, etc etc). And we know what happens in the long run. It all goes back to Ecclesiastes(and Job), you can be an "evil" person and prosper in this world. If this tiny lifespan is all there is, this is quite distressing. And physically there is nothing else. Apparently the best solution is to realize there are no rules but live as if they do per Voltaire(not necessarily Pascal).