Etrog (Citron) corresponds to the three sefirot of conscious emotion in the heart, which are Generosity ( Chesed ), Discipline ( Gevurah ), and Beauty (Tiferet )*, and so it inherits the following attributes:

Body: Heart and torso.
Kabbalistic Attribute: Beauty, as the balanced integration of love and fear, sponaneity and discipline, self-sacrifice and self-preservation.

Emotional Expression: Compassion, empathy.
Mental Expression: Taking the trouble to determine what another person really needs based on the unspoken realities of his/her heart and life.
Spiritual Expression: Empathizing with God's joys and pains (so to speak) and becoming more identified with that level of awareness than with one's own personal story.

Etrog's Healing Correspondences - Tiferet

Balanced, Rectified, God-Centered Expression: Glorifying God by creating beauty for His sake. Fulfilling one's religious obligations in the most beautiful way possible. Yearning to be pleasing in God's eyes.

When Contaminated by Serpent (Ego) Consciousness: Creating beauty for materialistic or lustful motives .

Pathological Expression: Obsessive-Compulsive Personality Disorder where one's commitment to beauty becomes fixated and superficial. (Obsessive-Compulsive Personality Disorder is defined as a pervasive pattern of preoccupation with orderliness, perfectionism, and mental and interpersonal control, at the expense or flexibility, openness, and efficiency.)

Too Little on the...

Emotional Plane: Lacking empathy. Lacking a sense of aesthetic.

Mental Plane: Inability to keep a secret because of over-empathizing with the one who would want to know.

Mental Plane: Flipping back and forth between extremes, of being too lenient and then too stringent, and back again.

Spiritual Plane: Lack of individuation because it requires the pursuit of skills and opportunities at the expense of others and this creates, at least temporarily, a state of imbalance. Inability to break symmetry as a necessary prerequisite to taking a further step.

Spiritual Plane: Observing the letter of the law, but ignoring its spirit (which is its aesthetic).