In the spiritual life it is important to remember that failures are as important, or perhaps even more important, than successes. To know when we will be tempted, and when we will most certainly fall, is a great strength because it gives us the opportunity to resist the near occasion of sin. Brother Lawrence of the Resurrection said of failure that it did not dismay him, but allowed him the opportunity for greater prayer because he could look to heaven and say "It is ever thus when I stray from you."
Spiritual "successes", on the other hand, can be a nearly certain road to derailment of spiritual life for those not well-inured and practiced in it. St. Teresa of Avila and St. John of the Cross warn about the temptation of seeking consolations in prayer. In seeking, you become attached to locutions, visions, or sweetnesses offered by the Lord, and your attention is distracted from Him. Your focus is no longer pure and true, it is diluted with another pleasure.
The most central pivot of our spiritual lives lies in this: Our entire joy is in the Lord. Everything that is done is done for love of Him. Without this pivot the lever with which we would move the world is merely a stick we use to beat it into submission. There is no loss so great as the loss of our spiritual center. There is no wandering so lonely as wandering away from Christ, for even though He is always with us, we lose sight of Him in a fog of our own making.