How do men of faith separate good miracles from bad miracles?

The most standard problem of miracles, attacked by Christian apologists, is that miracles break the immutable laws of physics, and therefore by definition are logically impossible. This was put forward best by David Hume. Many Christian apologists address and possibly rebute this, in various ways. But what about the second-order problem of miracles? That is, let's grant that the Creator and wonderworkers intervene in the laws of nature. How, then, do you guarantee that you get the right type of miracles and avoid the wrong type of miracles? That is, how do you get the happy miracles like Elisha filling the widows jars with superabundant oil, and avoid the unhappy miracles like turning into a halite formation? Every Christian who believes in miracles seems to be bent that they'll be something good, like getting an incurable cancer healed. But how does the Christian get these joyous miracles without also opening the possibility that they could accidentally turn someone to stone as a result? Why do faith pastors rejoice that they can multiply food but don't fear that they'll literally turn their son into a literal sheep? It sounds silly, but it's difficult to imagine a world where you allow only good energies to pour from Heaven (which is what all faithful Christians really want) without also allowing for evil energies from Greek mythology to flow from Gehenna. What is your reflection?