The Gemara in Eruvin (Daf 47) establishes the principle that "Ein Min Ha'kol Zocheh Ha'adam Li'lmod" a person is not necessarily able to study Torah successfully from all Rabbis. For this reason, the Gemara says, the Rabbis allowed a Kohen to walk through areas rendered Tamei (ritually impure) by Rabbinic enactment, in order to learn Torah from his preferred Rabbi. Even if there are competent Rabbis in his current location, nevertheless, since not every student is capable of learning successfully from every Rabbi, a Kohen may walk through an area the Rabbis had declared Tamei to hear Torah from the Rabbi from whom he learns most effectively.
Why is this the case? Why are some students more inclined to learn from some Rabbis than from others?
Rashi explains that not all teachers of Torah are endowed with the gift of brevity. Especially in the days when Torah was taught mostly by heart, rather than from texts, for many students it was necessary that the instructor taught in a concise manner. Therefore, many students prefer to study from a Rabbi who teaches clearly and concisely, rather than a more verbose instructor.
The Rashba, in his responsa, writes that scholarship and aptitude do not necessarily make one a successful teacher. Some Rabbis are blessed with a richer vocabulary and clarity of speech that allows for easier absorption of the material by the students. Therefore, a student might prefer to study from a certain Rabbi over another, even if he is less of a scholar, because of his clarity.
Thirdly, the Mekubalim (Kabbalists) discuss that when the souls of Rabbi and student originate from the same spiritual source, there is greater chemistry and a more successful transmission of the material. A student might not always identify a rational explanation for why he learns more effectively under one Rabbi than under another, because in some instances, the relationship stems from a spiritual kinship between the Rabbi and his students by virtue of the common source of their souls.
In conclusion, it should be noted that an important lesson emerges from this Halacha, allowing a Kohen to violate a Rabbinic prohibition to go hear the Rabbi of his choice. This unusual suspension of a law in the generally strict area of Tum'a (ritual impurity) reflects the integral role of Torah learning in a person's life. As we say each day in our prayers, "Ki Hem Chayenu Ve'orech Yamenu" Torah is "our lives and the length of our days." Since Torah is, in a very real sense, our life-source, the Rabbis were prepared to suspend their enactment to allow for one's maximum ability to study and absorb words of Torah.
