When I started my new blog: "On the buses - in Monmouthshire" I became instantly aware of the difficulty of choosing a pronoun. Other bloggers who perform amazing feats of endurance and initiative such as crawling round Wales on hands and knees use "I" as they are rightly proud of their epic achievements. Yet I am encouraging bus use, sight-seeing, short or medium walks and CAKE at the end. The French are so lucky to have "on", an all-purpose, gender-free pronoun, increasingly used instead of "nous". I do not wish to sound bossy by telling "you" what do do but "one" is too starchy and I have to use something. I think I will say "you" when I urge you to exert yourself and "I" when I sit down for tea and gateaux.
A fascinating footnote to this is that "your" can mean something close to "our" particularly if pronounced "yer". When Hamlet says to Horatio: There are more things in heaven and earth, Horatio,/Than are dreamt of in your philosophy," he is not accusing his friend of a limited imagination but means that anyone's philosophy may not include ghosts. This is the same extension of meaning as the gravedigger's: "your water is a sore decayer of your whoreson dead body." It is not truly possessive here and could be omitted in both instances.