Spiritual practice

Many spiritual teachings advocate a letting go of desires, concepts, beliefs, and so on, but I wonder if this is the most effective way to teach a spiritual practice. It seems to me that awareness, the simple act of just observing, of the various phenomena that we experience, either externally (sights, sounds, people, etc.) or internally (images, emotional reactions, internal dialogs, and so on), is the first thing that should be emphasized. Otherwise, the "letting go" may lead to repression, for example, the belief that I should let go of this desire could cause a negative reaction to wants that arise, that is to say, a repression of an internal state. This will only create an internal tension and a stronger re-arising of said want. It seems to me that emphasizing "just being" with whatever arises keeps us from reacting to and reinforcing our constructed, phenomenal world. Of course, this last statement begs the question, why should I not reinforce my constructed world of experience? A topic for another post.