What if Keith never got sick on Earth bc of his Galra genes?
So! He has no idea what it’s like! And in his younger years he was mad bc he never got to miss school, but growing up (specially when he went to live by himself on the desert) he started to appreciate this fact.
It isn’t until a while after they end up in space that he learns he is not entirely human, but it takes even longer (and one night chatting about everything with Pidge) that he (well, Pidge really, but whatever) connects the dots.
So, now he is in space. Quite close to a whole lot of Galras. And is because of this that, after a mission on an Empire ship, he ends up getting some kind of space flu.
It’s not so bad; a couple of coughs here and there, a stuffy nose, and some slight fever at night. But we’re talking about a man that has never been sick in his life!
What I’m actually thinking about is Keith, slightly feverish, telling the team something like “You know that feeling when you want to poop? It feels like that but in my nose!”.