do one's thing
Also, do one's own thing. Pursue one's interests or inclination; do what one does best or enjoys the most. For example, I really give him credit for doing his thing and not being discouraged by what the critics say, or Phyllis is busy doing her own thing, running the magazine and publishing books. Although this colloquialism became closely associated with the counterculture of the 1960s, it is actually much older. In one of his essays (1841) Ralph Waldo Emerson wrote: “But do your thing and I shall know you.” However, it came into wide use only during the mid-1900s.