CC Ādi 4.108

rādhikāra bhāva yaiche uddhava-darśane
sei bhāve matta prabhu rahe rātri-dine
Synonyms: 
rādhikāra — of Śrīmatī Rādhārāṇī; bhāva — emotion; yaiche — just as; uddhava-darśane — in seeing Śrī Uddhava; sei — that; bhāve — in the state; matta — maddened; prabhu — Lord Caitanya Mahāprabhu; rahe — remains; rātri-dine — day and night.
Translation: 
Just as Rādhikā went mad at the sight of Uddhava, so Lord Caitanya was obsessed day and night with the madness of separation.
Purport: 

Those under the shelter of the lotus feet of Śrī Caitanya Mahāprabhu can understand that His mode of worship of the Supreme Lord Kṛṣṇa in separation is the real worship of the Lord. When the feelings of separation become very intense, one attains the stage of meeting Śrī Kṛṣṇa.

So-called devotees like the sahajiyās cheaply imagine they are meeting Kṛṣṇa in Vṛndāvana. Such thinking may be useful, but actually meeting Kṛṣṇa is possible through the attitude of separation taught by Śrī Caitanya Mahāprabhu.