Bhagavad Gita 11.41सखेति मत्वा प्रसभं यदुक्तं हे कृष्ण हे यादव हे सखेति।अजानता महिमानं तवेदं मया प्रमादात्प्रणयेन वापि ॥

Although Kṛṣṇa is manifested before Arjuna in His universal form, Arjuna remembers his friendly relationship with Kṛṣṇa and is therefore asking pardon and requesting Kṛṣṇa to excuse him for the many informal gestures which arise out of friendship. He is admitting that formerly he did not know that Kṛṣṇa could assume such a universal form, although Kṛṣṇa explained it as his intimate friend. Arjuna did not know how many times he may have dishonored Kṛṣṇa by addressing Him “O my friend,” “O Kṛṣṇa,” “O Yādava,” etc., without acknowledging His opulence. But Kṛṣṇa is so kind and merciful that in spite of such opulence He played with Arjuna as a friend. Such is the transcendental loving reciprocation between the devotee and the Lord. The relationship between the living entity and Kṛṣṇa is fixed eternally; it cannot be forgotten, as we can see from the behavior of Arjuna. Although Arjuna has seen the opulence in the universal form, he cannot forget his friendly relationship with Kṛṣṇa.