You didn't, but it's a status effect in this game, which means that it's going to have an icon. There can be a visual indicator of the buff - like Astral Fire or Umbral Ice - but it's going to have an icon.

I'm not sure how "not having an icon" would suddenly make it so much cooler, anyways. Like...wow! You have a buff that isn't displayed next to your name! How cool is that?! (It isn't, and, presuming it offers bonuses like...say, being your tank stance/dps stance, there's no way that people can see which stance you're in unless they're looking at your weapon...which, given how busy the game can get at times, might not always be an option.)