Lan remembers seeing Minh at the bubble tea shop an hour ago. She knows he spent more time picking his outfit than lifting weights. With those four words and a smiley, she effectively told him, "You're doing too much, and I’m laughing at you." Minh didn't send another photo for the rest of the week.

The addition of the (a rolling-on-the-floor laughing emoji) is key—it signals that the speaker knows you're exaggerating, bragging, or being dramatic, and they aren't buying it. The Story of the "Gym Warrior"

In Vietnamese social media culture, is the ultimate "polite" eye-roll. It translates roughly to "Oh, is that so?" or "Wow, that's so impressive (not)."