I DON'T ALWAYS HAVE A CRUSH ON A GIRL / BUT WHEN I DO, SHE ALREADY HAS A BOYFRIEND
A The Most Interesting Man In The World meme.
The Most Interesting Man in the World is the bearded, silver-haired gentleman from Dos Equis beer's long-running ad campaign, played by actor Jonathan Goldsmith. In the ads he lived an impossibly legendary life and ended each one with "I don't always drink beer, but when I do, I prefer Dos Equis." The meme keeps that sentence shape: "I don't always X, but when I do, I Y" - perfect for confessing an odd habit with total, effortless confidence.