Positive: An unexpected benefit also known as luck or serendipity.
Negative: A unexpected side effect in addition to the desired effect.
Perverse: An intended solution which exacerbates the problem that the action was intended to correct.
Inasmuch as Murphy allows only for perverse outcomes, we must assume that he was an optimist.
Life is far too complex for anyone to fully master their little corners of it. Thus, isn't it better that we avoid centralized control wherein the unintended consequences of decisions affect society at large? I am perfectly willing to suffer the fate of my own decisions. I'd rather not suffer their mistakes, too. How about you?
Let's look at a couple of examples.
California (Rather, progressives who dominate California politics) are considering taxing Californians for the number of miles they drive. Why? Well, it seems that they taxed gasoline high enough to drive Californians into fuel-efficient cars such as the Pius (make that Prius). As an unintended consequence, gas tax revenues have fallen significantly. Thus, owners of fuel-efficient cars may find themselves paying a premium, possibly more than owners of the gas-guzzlers, for acting socially responsible.
Americans are beginning to face the unintended consequences of the Affordable Care Act (popularly known as Obamacare). Medical service facilities have been closing and medical service providers have been emigrating back to the homelands they came from now that the government is regulating healthcare in the United States. Taxpayers who decided to take penalties rather than purchase healthcare or who couldn't afford government mandated healthcare policies will soon receive bills from the IRS, far beyond the penalties they were expecting. Those who received subsidies to purchase healthcare may have to pay them back.
Ultimately, nothing will change until constituencies begin considering the consequences of their votes rather than the immediate benefit of electing those who simply promise to loot on their behalf.