"No matter how mundane you think your job is, to someone else it's interesting."
That's how Masello begins his short essay on rule #33. His overall point is that the everyday life you might think is mundane may very well be fascinating to your readers. And it's a good point to keep in mind. When we write, many of us are more interested in the exotic worlds we create, when what our readers might really want to see is the everyday world they know little about.
The most explicit examples of this that I can think of happened in real life.
Back in 1996, when attending Worldcon in Los Angeles, Nomi and I had a chance to visit the set of one of our favorite television shows. We were taken around the set by the assistant to the executive producer, and over the course of the tour we met one of the actresses working on the show.
Both the assistant and the actress were delighted to meet us, and in the course of talking they asked about our own lives. At the time, I was working full-time as a Science teacher, and they couldn't hear too much about it. Here they were, working in television, which I thought of as exotic, and they wanted to know how I structured my lessons or decided how much homework to assign each night. The actress was also a professional stuntwoman, and yet here she was, finding my everyday job as intriguing as I found hers.
(Of course, having actually done extra work in three movies, I actually do have an idea of how boring a television or movie set can be.)
Another example of this I can recall was from the summer of 1989, when I took a job working at Los Alamos National Laboratory. Many of my friends at Harvard were fascinated by the stories I told of the lab job and the community of Los Alamos, whereas the people I met at Los Alamos couldn't get enough of my stories about what it was like being a Harvard student. In both cases, their own lives felt mundane because that was what they did, day in and day out, but the other world was exotic and full of fascination.
This happens at science fiction conventions, too. I used to work on the programming committee of a local convention, and to be honest, the last thing we needed was another science fiction writer offering to be a programming participant because they wrote science fiction. Much more valuable were those writers who had day job experience that they could bring to the table. If you're at a science fiction convention, would you rather hear a full-time writer talk about writing or a stockbroker/writer discuss how she used her experience as a day trader to flesh out her novel about stockbrokers in the future?
In short, as a writer you've got a lot more to bring to the table than you may realize. So bring it along, and let your readers learn.