That's one of the things Pope Francis mentioned in his latest Apostolic Exhortation, Gaudete et exsultate. We have to know what true sanctity is, how it is attained, where to find it, how to sustain it.
We cannot deny there are many fake forms of holiness today, and we have to identify and avoid them. One of the fake forms is Gnosticism.
In paragraph 36 of the document, the Pope describes Gnosticism as "a purely subjective faith whose only interest is a certain experience or a set of ideas and bits of information which are meant to console and enlighten, but which ultimately keep one imprisoned in his or her own thoughts and feelings."
In paragraph 37, he points out the consequence Gnosticism: "Throughout the history of the Church it has always been clear that a person's perfection is measured not by the information or knowledge they possess, but by the depth of their charity.
"Gnostics do not understand this, because they judge others based on their ability to understand the complexity of certain doctrines. They think of the intellect as separate from the flesh, and thus become incapable of touching Christ's suffering flesh in others, locked up as they are in an encyclopaedia of abstractions. In the end, by disembodying the mystery, they prefer 'a God without Christ, a Christ without the Church, a Church without her people."
This must be clear. While knowledge of the doctrine of the faith is indispensable, it should not be separated from the most important element of sanctity; charity.
That's why St. Paul said: "These three remain: faith, hope and love. But the greatest of these is love." (1 Cor 13,13) Earlier, he said: "If I speak in the tongues of men or of angels, but do not have love, I am only a resounding gong or a clanging cymbal. If I have the gift of prophecy and can fathom all mysteries and all knowledge, and if I have a faith that can move mountains, but do not have love, I am nothing." (1-2)
This love should be the love shown and lived by Christ himself. And what kind of love is shown and lived by Christ? A love that knows how to bear all the sins of men. It's not a love concerned about the requirements of justice, because in the end, despite our best efforts, we know we can never fully meet these requirements.
So we have to see to it our growth in the knowledge of the doctrine of our faith should lead us in the growth of the charity as shown by Christ. If we notice that our doctrinal knowledge makes us feel superior, leading us to look down on others, we are on the wrong track toward true holiness.
True holiness should make us always humble, compassionate, patient, merciful, willing to bear the burden of others, never mind if we find it unfair. True holiness is living the beatitudes as articulated by Christ.