You cannot see your own life clearly while you're in the middle of it. You simply will not be able to re-evaluate your problems while you are in the middle of it. You need distance, real and psychological distance. Distance from your old, familiar self. The environment where you are now is full of triggers that pull you straight back into old thought patterns. The kitchen where you had the fight. The commute where you feel the boredom. The gym where you check the mirror and feel the years.
There are actually easy to understand psychological reasons why a change of environment causes a change of perspective. If you take away familiar cues, you will be forced to think about basic things again — what to eat, how to get somewhere, who these people are. You will need to re-examine old assumptions instead of just re-using the old ones. What also gives you chance to change perspective is just distance itself, in time or in space. From a distance, the same things start to look smaller and more general: you will start to see the patterns, not the incidents.
In addition, that changed environment is especially effective if it is very different from our usual environment: a more natural environment than our offices and cities. You could probably fill a small library with books on the back-to-nature argument, and I am pretty sure you heard it all before. I am pretty sure you experienced this yourself at one point, even if only through a walk in the park. I will limit myself here to telling you that our brains were not evolved to function in a crowded, information-dense, overstimulating artificial environment, and that living in such an environment will inevitably lead to serious problems. In short, you probably could do with some quiet nature, and I don’t think I need to convince you of this.
In your old environment, people know who and what you are, and they force you into that role. You have accepted that identity, and it feels like it IS you. But it is not. It is just a role you play in a certain environment. Of course, you have a personality, we will come back to that later. But with that personality you can play many, many roles. If you had been born, say, in China, with your personality, would you be what you are now? I do not think so.