English is actually one of fairly few languages where all nouns are just neutral.
Though admittedly, I never managed to get a good feeling for languages requiring cases (genitive, dative, accustaive, what-have-you, like German or Latin). Guess it's partly down to what you grow up with.
I understand the concept but how each is decided was never explained really, or more likely it was and I just didn't pay attention, so it just felt like to get by I needed to roam around with a conjugating dictionary.