There are people who by nature, physically as well as spiritually, tend toward melancholy.
A tempestuous life–whether of holiness or of impurity–holds no attraction for them.
Contentment lies in quiet continuity.
If they have an intellectual bent and if matters of the spirit interest them, then the coziest means for self-realization is to sit and study.
The latter requires no self-sacrifice; it is the self-expression of a bookworm.
Such an individual devotes every spare moment to Torah study.
There is no contest between a Godly soul and an animal soul; this is his animal soul.
We could reasonably expect that, intellectual though he may be, he might have to struggle with his disposition in another plane, namely, sexual desire.
The capacity for sexual pleasure differs from one person to the next.
And a lack of sensuality, an absence of pleasure in eating or drinking, is no indication of spiritual achievement.
Someone may not pay any attention to what he eats or what he sees.
So, too, with sexual desire.
Such an individual can sit in a study hall and be occupied with the performance of the commandments while the world around him presents no temptation.
He gets dressed every morning, has his breakfast, and goes about his business.
His single-minded focus on Torah study is not from a magnetic attraction to holiness; he is disinclined by nature to do anything else.
He could be a clerk, a professor, or a rabbi–any of these, with no change in his disposition.
–Rabbi Adin Steinsaltz
From Learning from the Tanya, Chapter 15, by Rabbi Adin Steinsaltz