SB 11.21.22

viṣayābhiniveśena
 nātmānaṁ veda nāparam
vṛkṣa jīvikayā jīvan
 vyarthaṁ bhastreva yaḥ śvasan
Synonyms: 
viṣaya — in sense gratification; abhiniveśena — by overabsorption; na — not; ātmānam — himself; veda — knows; na — nor; aparam — another; vṛkṣa — of a tree; jīvakayā — by the lifestyle; jīvan — living; vyartham — in vain; bhastrā iva — just like a bellows; yaḥ — who; śvasan — is breathing.
Translation: 
Because of absorption in sense gratification, one cannot recognize himself or others. Living uselessly in ignorance like a tree, one is merely breathing just like a bellows.
Purport: 

Just as trees, having no means of defending themselves, are always being cut down, similarly, the conditioned souls are constantly being cut down by the cruel laws of nature, which impose innumerable miseries culminating in sudden death. Although foolish people think they are helping themselves and others, they actually do not know their own identity, nor the identities of their so-called friends and relatives. Absorbed in gratifying the senses of the external body, they spend their lives uselessly, without spiritual profit. This useless lifestyle can be transformed into a perfect life simply by chanting the holy names of God in Kṛṣṇa consciousness, as recommended by Śrī Caitanya Mahāprabhu.