Start 10,000 traders with no edge. After three years, pure chance leaves several hundred with strong records, and those are the ones with courses, followings and screenshots. The thousands who quit are not visible, which is survivorship-bias operating on people rather than funds.
It shows up in specific, checkable ways: records that begin at a convenient date, composites that exclude closed accounts, results shown from the best of several strategies, and demo or replay periods presented alongside live ones. The single most useful question about any record is what was excluded and when the reporting started.
Apply the same scepticism to yourself. If you have run four strategies and report the best, your own record is selected too - which is the individual version of sharpe-inflation.
Related: survivorship-bias, luck-versus-skill, sharpe-inflation, incubation-period