To recap, UX is like a kitchen (at a restaurant). There are many employees doing their own jobs, but each person/job must ultimately work together for your successful dining experience. The four components needed include: fresh ingredients (aka great content like copy, imagery, videos, etc), a clean kitchen (aka clean code, clean file names, easy to use intranet), a beautiful dining area (aka a beautiful front-end design), and fast service (aka optimized code to serve the user data quickly). If, as a diner, you end up waiting 50 minutes for your food for example, you will likely be frustrated, upset, and never come back to that restaurant again. This will be the same result of a user visiting your website, with a slow load time. So user experience should be important to everyone on a development team. Everyone's job is important.
According to Nelson, an example of a great user experience is Google.com. Google is intuitive, simple, and easy to use. At one point, Google's search competitor was Yahoo.com. Both websites can do the same thing, by why did Google prevail? No one ever says they've "yahooed" something. Perhaps it's because Google has a more pleasant user experience! Google is basically just a search bar, whereas Yahoo is cluttered with everything from the news to politics to the weather.
UX is so serious that there are scientists who specifically study the way we use products. For example on a website, which type of button attracts the most clicks? Round ones, square ones, red ones, etc? The answer to that question may even affect the amount of sales from that site! On that note, Nelson recommended getting to know analytics and AB testing. Lastly, if you'd like to learn more about this topic, he recommends checking out the articles written by Digital Telepathy. And if you want a good user dining experience in San Diego, he recommends Juniper & Ivy.