Pursue one's own interests or inclinations; do what one does best or enjoys most. Also 'do one's own thing.'
Examples:
- I really give him credit for doing his thing and not being discouraged by what the critics say.
- Phyllis is busy doing her own thing, running the magazine and publishing books.
Origin: Though associated with 1960s counterculture, Ralph Waldo Emerson wrote it in 1841; came into wide use mid-1900s.