Feeling quite fond of my mother

It's family season and I am at my parents' house in Devon. My mother even collected me this morning and drove me all the way down. It took us more than seven hours, though we did stop for an hour or so with my aunt. My mother's sat nav device is giving her trouble -- which sounds like a very posh thing to say, but my dad really needs one for his work, so my mum's car has one in case. It sometimes tells her to turn right where there are no turnings, and take the fifth exit from imaginary roundabouts. "The thing is", she said embarrassedly, "you know how oftentimes to win us to our harm the instruments of darkness tell us truths and win us with honest trifles?" I said I quite understood; the sat nat has become an instrument of darkness. Later I found the quote immediately, because I knew it would be in Macbeth. My mother isn't bothered about other Shakespeare or literature in general really, but she loves Macbeth. When I was very small I would sit on her lap and we would do the witches together in funny voices.

My mother is a loony, but in an excellent way. She has odd habits, like sometimes when she goes to the supermarket she'll only buy things beginning with the same letter; in my time I have come up with lots of circumlocutions for milk, like "bovine lactations". She once wrote a very moving poem about her love for cardboard boxes. My father is even more of a loony, so it's a wonder I turned out so normal.