I think if we were honest with ourselves, we would recognize that we like to measure how things are going with our spiritual life. We tend to have certain aspects of the spiritual life towards which we gravitate, and we tend to project our preferences onto others. To be honest, this tendency is not something we can make magically go away. As with other aspects of our fallen nature, the key often lies in not letting such things rule how we engage with the world.
However, we have to recognize that holiness cannot be measured. In our life, this becomes particularly hazardous when we look for signs that we are holy. Then Cardinal Ratzinger (i.e. Pope Benedict XVI) wrote a great document on prayer in which he highlights some of the dangers of the spiritual life.In particular, he turned towards two early heresies that tend to resurface from time to time.
The first is Gnosticism. Their view was that holiness involved a kind of special knowledge. Thus they emphasized the intellect over and against the body and the world. Although its claims might be quite foreign to our heavily pragmatic culture, we can have a similar tendency to focus on the acquisition of knowledge. We can tend to measure our spiritual life by the pursuit of trivia. What we must learn is that the pursuit of knowledge is not a kind of moral absolute. It has its limits.
The second heresy is Messalianism. This heresy taught that holiness can be measured by spiritual experience. They held that certain sensations and certain mystical experiences were proof that one was in right relationship with God. Although few people would argue such a position out loud, we can hold this view implicitly. We might believe we are holy because we have unique spiritual experiences, or the reverse. We might believe that we have sinned when we experience suffering and aridity.
To both these heresies, Cardinal Ratzinger presents the answer of early Christians. They argued that the central characteristic of holiness is Christian love. While knowledge is useful and experience is certainly an aspect of the spiritual life, the true measure is whether we love God with our whole heart and whether we love our neighbor as ourselves. It seems so simple, but yet we need to be constantly reminded of it. In the end, only three things will remain, faith, hope, and love, and the greatest of these is love (1 Corinthians 13). Also, we have to recognize that how much we love is always somewhat mysterious. It is not based on feelings or passing moods, but is the enduring quality of heart that lives in perfect self-forgetting
Understanding this deep spiritual truth, however, does not make it easy to live out. We all learn pretty quickly in life that our love needs to grow; it needs to mature and ripen. We also learn that this transformation is an on-going process, one with many ups and downs. We learn constantly that we must turn to the Lord and seek him above all things. This is the heart of prayer, turning to God in a posture of complete dependence, the posture of a child.