The reason is not, as one said, to avoid a traffic jam. As we do pradakshina, the Lord is always on our right. In India, the right side symbolizes very special. As we circumambulate the sanctum sanctorum we remember that we should lead a auspicious life of righteousness, with the Lord, who is the indispensable source of help and strength, as our guide: the “right hand” . The commandment of the Indian scriptures: matrudevo bhava, pitrudevo bhava, acharyadevo bhava. You can consider your parents and teachers as you would with the Lord. In this spirit, we also do pradakshina with our parents and divine characters.
After the culmination of traditional worship (pooja), we usually do pradakshina around us. In this way, we recognize and remember the supreme deity in us, who is idolized only in the form of the Lord whom we worship outside.