John swears. A lot. Sherlock is sure there's a pattern to it, triggers and probabilities of particular words and all that, and he's got to find out why.
So he experiments with making John mad at various times/places/situations and secretly records all the data. John finds out and swears some more.
John swears; Sherlock experiments
So he experiments with making John mad at various times/places/situations and secretly records all the data. John finds out and swears some more.