I don't do it to "sound like an expert," but to help newbies better understand the things. I'm an NRA instructor with 16 years experience, so I've done quite a bit of that. The DA/SA difference is not a difficult concept, if explained properly.
It’s the so-called experts who dig up the strange terms which don’t help matters. The NRA claims I’m a rifle expert but I just tell people I’m a student. I defy anyone who could ever claim they know it all. That’s impossible.