Hello! No Friday Fiction Feed last week because I am lame. But I have one this week because I'm not super-lame! Yay.
How many characters have allergies? Few, if any. But how many people do you know have allergies? Odds are, a large amount. Allergies are just one of those little side-comments that can make a characters seem more human and real. It doesn't have to be huge. Just a, "Want a piece of gum? Oh, it's strawberry flavoured, I'm allergic, sorry." BOOM. Character realism in fewer than ten words.
So go ahead and give your character an allergy this week. Make them break out in hives or sneeze! (Or die, if you are feeling bloodthirsty.) Give them a funny allergic reaction story. Just try and humanize those characters a little bit*.
*Bonus points if you are humanizing aliens.