It is not like studying German, where you mull along, in a groping, uncertain way, for thirty years; and at last, just as you think you've got it, they spring the subjunctive on you, and there you are. No- and I see now plainly enough, that the great pity about the German language is, that you can't fall off it and hurt yourself. There is nothing like that feature to make you attend strictly to business.
Mark Twain, General Press (2016). “The Complete Works of Mark Twain: All 13 Novels, Short Stories, Poetry and Essays”, p.3129, GENERAL PRESS