It's funny but some of what Anders says is true. The company I work for makes telecommunications antennas and filters and all of our engineering drawings use imperial measurements (I live in Canada). When I asked why we use this, as mentioned, collection of random measurements I learned that the company was founded by an American 65 years ago and to convert our thousands of drawings into metric is unfeasible. It's particularly funny because our current engineers are mainly Chinese immigrants who are trained to use metric and they absolutely hate with a passion how they have to make measurements in fractions of an inch as opposed to using millimetres.
Tl;dr imperial sucks collosal dick.