Okay, here's the thing I really don't understand.
Aang got his tattoo's from the monks, right? The arrows represent the respect for the flying bisons, who are the ones who learned them airbending. Why, oh why do these tattoo's glow when Aang goes in the avatar state? Maybe the monks already knew about Aang being the avatar, and that might be the reason why they gave him some kind of ''special and spiritual'' (lol) tattoo, but why would they do that???I mean, it's prety obvious to see when an avatar is in the avatar state, their eyes glow! They don't need to give him special ''glow in the dark'' tattoo's as an extra warning to back off when he's in this state. It's a true mystery for me, and I hope that you guys might have the/an answer for me, or maybe no one knows and we just have to hope that they'll explain this thing later in the show.