The Greta Thunberg meme primarily stems from her emotional and powerful speech at the 2019 UN Climate Action Summit, where her phrase 'How dare you!' became an overnight sensation. The template features her intense facial expressions, capturing a sense of righteous indignation or extreme disapproval. While originally rooted in environmental activism, the internet quickly adapted the image to mock everyday inconveniences, hypocritical behavior, or general frustrations. It remains a staple for reacting to situations where someone’s actions seem shockingly inappropriate or when expressing mock outrage over trivial matters.