Chanting this mantra makes you feel complete and connect to the Universe. It means whatever found in this Universe is complete and infinite. Anything composed of something which is complete is also complete.
And when this complete will removes from this Universe then infinity will remain.
ॐ पूर्णमदः पूर्णमिदं पूर्णात्पूर्णमुदच्यते ।
पूर्णस्य पूर्णमादाय पूर्णमेवावशिष्यते ॥
ॐ शान्तिः शान्तिः शान्तिः ॥
And when this complete will removes from this Universe then infinity will remain.
ॐ पूर्णमदः पूर्णमिदं पूर्णात्पूर्णमुदच्यते ।
पूर्णस्य पूर्णमादाय पूर्णमेवावशिष्यते ॥
ॐ शान्तिः शान्तिः शान्तिः ॥