mind one's own business

Verb

mind one's own business (third-person singular simple present minds one's own business, present participle minding one's own business, simple past and past participle minded one's own business)

1. (idiomatic) To concern oneself only with what is of interest to oneself and not interfere in the affairs of others.
   • I was just walking down the road, minding my own business, when I was attacked by a mugger.
   • The idea is but too prevalent in almost every community, that a man has discharged his duties as a citizen, well enough, if he minds his own business and does not meddle with the affairs of his neighbours. "Look out for Number One," is a great fundamental maxim, which is in every body's mouth, and...1846, “Moral Responsibilities”, in The British Friend: A Monthly Journal Chiefly Devoted to the Interests of the Society of Friends, volume 4, number 8, page 204

   Synonyms:

   stick to one's knitting, MYOB, paddle one's own canoe, skate one's lane, stay in one's lane