I got all the rules (declensions, conjugations, etc) but I always had trouble piecing them collectively. A lot of the declension endings would be the same (such as 4th declension nouns) and it was hard for me to differentiate between a nominative and accusative in the context of a sentence. Hence I never studied Latin in college. I'm sure the world is a much better place for that. Wow, I can't believe I am reopening old wounds from 12 years ago ;)
I genuinely believe the single perfect test score is also empirical proof of the difficulty of Latin in an English-speaking world...
I would much rather parse MIPS assembly all day than read Latin.