Using web dev tools / inspector during a screen cast demo, either to modify a style or to show a site/app's responsive behavior. Simple, I know, but it comes off as some form of wizardry to many clients.
"Comic Sans is licensed by Microsoft and can't be used on the web" "When we build websites, we first write it in another language and then pass it through a program that translates it so that browsers understand it. Adding Comic Sans would require us to make changes deep in the 'translator' program that is supplied by a third party." "Comic Sans is cancer, see these links. Designers all over the world hate it. If I had a site with Comic Sans on it in my resume, I would seem very unprofessional to a lot of potential clients."
I usually explain them the problem I'm facing in non-technical terms.
Of course, and I bill my time spent doing this.