The line comes from Memati, the hot tempered enforcer in Kurtlar Vadisi, the long running Turkish crime drama that began in 2003, played by Gürkan Uygun. His short fuse and blunt street slang made many of his outbursts easy to lift as standalone reactions. Online, this 'yeter lan' clip spread through Turkish meme pages, edits and soundboards as a universal fed up signal, detached from its original scene. It stays popular because the shout needs no context and translates across languages through delivery alone.