YAGNI is not Gangnam Style

YAGNI principle - "You Aren't Gonna Need It" is not as popular as other Agile principles like KISS and DRY maybe because it doesn't have a sexy name.

Behind the practice it emphasise on "doing the simplest thing that could possibly work" in case of bloating software larger and more complicated. Never add functionality early and keep the system uncluttered with extra stuff you guess will be used later.