The line comes from Get Smart, the 1960s American spy comedy starring Don Adams as bumbling secret agent Maxwell Smart. Smart used 'Missed it by that much' after narrow escapes and failed plans, often holding his fingers close together to show how small the margin was. The phrase entered everyday language as a way to describe a narrow failure, and later spread online as a short reaction clip. Creators still reuse it because it instantly explains a near miss without needing any setup.