ऊर्ध्वं गच्छन्ति सत्त्वस्था मध्ये तिष्ठन्ति राजसाः ।
जघन्यगुणवृत्तिस्था अधो गच्छन्ति तामसाः ॥

ūrdhvaṃ gacchanti sattvasthā madhye tiṣṭhanti rājasā: |
jaghanya-guṇa-vṛttisthā adho gacchanti tāmasā: || 14.18 ||

The prudent seeker should thus foster a wholesome perception to guide him always:

Sāttvika people go upwards, rājasika ones remain in the middle, while the tāmasika lot, given to basest qualities and activities, go downwards.

The general sāttvika influence of prakṛti will cause the birth and growth of individuals who will be imbued with preponderance of sāttvika characteristics. They will always strive for goodness, purity and evolution. Equally so, there will be those given to neither extreme purity nor its opposite. Governed by rajo-guṇa, its propensities, they will go after a variety of actions motivated by desire and the rest. As a counter to both, will be the others dominated by the tāmasika tendencies. They will be courting degeneration and downfall.

The world at any time will be a good mixture of all the three groups. Prakṛti is a charming blend of these three guṇas, resulting in the preservation of the good, the bad and the otherwise. To live in the world is to be accepting all these and being in harmony with them.