I think actually this is just our subconscious playing avoidance tactics with us; always striving to find happiness outside of ourselves, not wanting to have to look closer to home and realise that all the answers lie within us (there's a famous quote there somewhere!).
The personal growth industry is built on the idea that we can get fired up by a walk-on-coals weekend seminar or a new book and then radically change our life. Most of us have been 'motivated' in this way, and I'm not saying it's bad. But what tends to happen? A couple of weeks after the big epiphany we go back to our normal selves and the life we had before.