Is English Hard?

Linguists tend to consider English grammatically simple - i.e., there are no gendered nouns, and verbs only conjugate a couple of ways. Contrast this with a language like Finnish, which has a legendarily difficult verb/noun agreement system, not to mention pronunciation which non-natives find mystifying. Japanese also lacks gendered nouns, and verb conjugation follows simple and universal rules, but learning to write is pretty much a lifelong struggle. So what are the hard points of English?

I think spelling is one of them. Like kanji, English spelling rules are often case-by-case, with no obvious principle governing them. Think about it - why are "bus" and "busy" pronounced so differently, while "bluff" and "tough" are strangely pronounced the same.