As stated above, Testosterone-Enanthate is perfect for all levels of performance experience, and further, is the perfect base or foundation of any anabolic steroid cycle. Regardless of your experience, your body will not become so accustomed to the hormone that it no longer works; after all, we're simply talking about testosterone, a hormone you have always produced naturally. In any case, the total dosing of Testosterone-Enanthate can vary tremendously between beginners and advanced users, but a beginner's dose will work for any man regardless of experience. For the purpose of performance enhancement, most will need a minimum of 500mg per week, with 1,000mg per week normally being the perfect dose for advanced supplementation. Doses that go above the 1,000mg per week mark severely open the door to possible aromatizing side-effects, and the additional gains will more than likely not outweigh this factor. Advanced performance enhancers who supplement with 1,000mg of Testosterone-Enanthate per week yet want more of a punch will always be better served adding in other anabolic steroids on top of their Testosterone-Enanthate; this we can guarantee.
The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".   Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.  The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.  Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.     
The partition coefficient of the ester in question is important because is effects how long the drug itself stays in the system. If the testosterone transfers too quickly from the oil to the blood, the result is a sudden spike in testosterone which then rapidly drops once the dose has been used up. In the example of free testosterone injected into the muscle from a water suspension (as in Aquiviron, mentioned above), the testosterone is essentially immediately available to the bloodstream due to its low partition coefficient, and thus there is an immediate spike of testosterone which is used up quickly in the body.