When it came to the notorious split infinitive (e.g., “to boldly go where no man . . .”), he observed that those English speakers who neither know nor care about them “are to be envied” by the unhappy few who do.
My favourite passages in The King's English, written by Fowler with his brother in 1906, are about slang:
Awfully nice is an expression than which few can be sillier; but to have succeeded in going through life without saying it a certain number of times is as bad as having no redeeming vice.
Indeed only the other day I was worrying about "rather ordinary".
* See section on "Words whose meaning is misapprehended without apparent cause", in The King's English; or perhaps under the wanton use of foreign words.