Ear Worm: Here, Yeller! Come back, Yeller! Best, doggone dog in the west....
Sequelitis: Savage Sam (the movie at least) is not as well-regarded as Old Yeller.
Too Dumb to Live: Arliss tries to open up the corn crib that contains a rabid Old Yeller, even when can clearly see the dog snarling, lunging, barking, and acting not at all like the cuddly family pet.
Values Dissonance: It can be very difficult for modern parents to stomach the idea of a mother letting her son be the one to kill his beloved pet, rather than doing it herself and sparing him the trauma. Sure, back then he would have been expected to "man up" and do it himself, but in the 21st century, few people would dream of even allowing their child to witness the euthanasia, let alone commit it.