We understand how you feel. We recognize the high cost of misdirected hope: the disappointment that comes from over-investing faith, or wrongly investing faith, in things that cannot -- or will not -- fulfill our hopes.
But the greatest dangers of misplaced faith come not from disappointment itself, but from over-reaction to it. Here we are speaking of the tendency to over-generalize about the dangers of life, and thereby get stuck in the muck of distrust.
Spiritual growth is built of "leaps of faith." Chronically distrusting people are too fearful to be sufficiently spiritually adventurous for their own good. They have so little trust and faith in themselves, others, God, and the Universe Process that they simply will NOT take the kind of leaps necessary for their higher dreams to be fulfilled. They are too distrustful of their own judgment to believe they could live on the basis of their own intuition.
Thus, while you are wise NOT to misdirect your trust, you had better take pains not to give up trusting entirely.
Oftentimes, excessive distrust is a result of seeing situations in terms that are too black and white. People who have made a great leap in the past sometimes say, "That choice was a big mistake." Quite possibly, they are giving themselves far too little credit for the outcome when they say the leap itself was wrong! They may have been right in making the leap, but then they simply exhausted the educational opportunity that it provided. Or perhaps it was simply time to graduate, without regret, to a new venue. Or perhaps they never trusted their chosen situation enough to find out what it really was. Or possibly, they themselves ruined that potentially good opportunity with runaway fear and irrational blame.
Most circumstances in life are mixed -- not all black and white. So why say that a decision that had SOME merit was ALL bad? And even in the unimaginable case that it really WAS all bad, the only thing lost is a little time. You still have your freedom of action and freedom of choice. All it takes to regain your ability to trust is the willingness to consider that you can change your mind, you can outgrow a DECENT choice, you can learn a HELPFUL lesson. Not much to ask, is it?