Dale, cats
Dale is not allergic to cats, but he is terrified of them. It's not one of the things he publicizes, given that there are more pressing matters at hand, and the cat population seems to have gone drastically down due to the walkers surviving on anything living.
His aunt had lived next door when he was small, and his mother would always take him over during the summers when he was too young to run around the neighborhood by himself or with his friends. She and her sister would sit on the front porch drinking sweet tea and playing Scrabble. His aunt would tell him to go play nice with her kitties.
Only her kitties weren't nice; they were sent straight from Lucifer himself to torment him. Scratches and bites would pepper his arms and legs by the end of the summer, and his mother never believed him when he said all he tried to do was pet the cats, and that they hated him.
Dale has tried to get over his fear a couple of times, but despite wanting to make friends with at least one feline, they all seem to dislike him from the start. Dogs, on the other hand, would go out of their way to say hi to him and get a pat on the head. Dale likes that just fine, knowing that not all animals hate him on sight.
A month after leaving the farm, Dale is keeping watch while the others are asleep, and all is quiet. Andrea climbs up for a change of guard when it happens. He hears a rustling noise in the bushes, and it doesn't sound like a walker, but there aren't many creatures that are out and about at two in the morning that would come near a small camp fire.
When the cat slinks out of the brush, sniffing the air and looking around, Andrea lets out a little "awww, kitty".
Dale tries to remember how to breathe and not shriek like a frightened child. He also has to remember that ammunition is limited and shooting the cat is out of the question, which is why he slowly lowers his rifle that had automatically trained on the shaking brush.
"Dale?" Andrea is looking at him, perplexed. "It's just a cat, what's wrong with you? You allergic?"
Dale does something he's never done before in Andrea's presence: he lies through his teeth and doesn't regret it for a second.
"Deathly allergic; hair, dander, spit, I can't have it anywhere near me or my throat closes up. Shoo it away, would you?" He gives her the big, pleading puppy eyes that nobody realizes he knows he's good at, and rejoices internally when she clambers off the RV to remove the hellion from camp.
He may be the oldest among them, but that didn't mean he can't act childish every once in a while. With that in mind, he sticks his tongue out at the cat when it runs away from Andrea and back into the woods.