The cause of greed for Kṛṣṇa rasa

Where does such spiritual greed for Kṛṣṇa rasa come from? Rūpa Bābājī summarizes this in Bhakti-rasāmṛta-sindhu 1.2.292:

tat-tad-bhāvādi-mādhurye śrute dhīr yad apekñate |
nātra śāstraṁ na yuktiṁ ca tal lobhotpatti-lakñaṇam || BRS 1.2.292.

"The appearance of that greed is indicated when the intelligence does not
depend on (previous) rules of scripture and logic, after realizing to some degree the
sweetness of the love of the Vraja-vāsīs through the process of hearing from the scriptures."

When one has gained some perception, from hearing the Bhāgavata Purāṇa or other books on the Lord's sports written by rapturous devotees, that all of Kṛṣṇa's senses are pleased by the feelings, beauty and qualities of the residents of Vraja such as Nanda and Yaśodā, an attitude arises that is indifferent to scripture or argument and is a symptom of the development of eagerness or greed (lobha). This attitude is, more specifically, the innate desire for the sweetness of those various moods: "May I also have the same kinds of feelings and qualities."

Even though attraction to the mood of the residents of Vrindavan is so natural, not all persons develop it instantly upon first hearing about it. The Caitanya-caritāmṛta says:

hā śuni lubdha hay kono bhāgyavān. CC 2.22.87.

"Some rare fortunate soul develops greed on hearing the glories of the residents of Vrindavan."

One needs the mercy of a devotee who is himself endowed with this spirit and the candidate must be possessed of certain qualities on his own-a certain lucidity or clearness of mind-before such greed can appear. Therefore, Rūpa says in Bhakti-rasāmṛta-sindhu (1.2.309) that it is kṛpaika-labhyā, "only available through the mercy of the Lord and his devotees."

In the Bhakti-sandarbha 310("Treatise on Devotion"), Śrī Jīva describes the development of greed in the following way:

tādṛśa-rāga-sudhākara-karābhāsa-samullasita-hṛdaya-sphaṭika-maṇeḥ sādhakasya tat-paripāṭīñv api rucir jāyate.

A devotee whose heart is clear like a crystal will find that when the rays of the moon-like devotion of the residents of Vraja fall upon it, it lights up and takes on that glow itself, i.e., eagerness manifests itself in his heart. Then a curiosity about the dealings or feelings or passions of the eternally perfect residents of Vraja such as Nanda, Yaśodā, etc., arises in the practitioner. In other words, a desire to know more about the patterns of their feelings occurs and he develops a taste or hunger for those patterns.