The Most Interesting Man in the World

Where it came from
This is from a Dos Equis beer ad campaign that started around 2006. The character became iconic throughout the late 2000s and 2010s as the face of their marketing.
So basically, this dude in the ads is just impossibly cool and sophisticated. He's always in some glamorous situation, looking distinguished AF with that salt-and-pepper hair and beard, usually with a beer nearby. The meme took off because people would use his image with the caption 'I don't always [do something], but when I do, I [do it in the most extra/impressive way possible].' It's become this format for humble-bragging or joking about doing mundane things in the most ridiculously over-the-top manner. The appeal is that he just radiates unearned confidence and class, which makes the contrast hilarious when you pair it with something completely ordinary or stupid.
Search interest, over time
↳ data courtesy of google trends


