Instructing and teaching is part of your personality.
Some people can't help but instruct by their very nature about the things they enjoy.
It doesn't matter if they have an official tick in the box or not people will learn off them by default because they have the knack of instructing.
Once Chuck get's to the smelling of wee stage sitting at the local FBO with his dog getting some peace from the wife. A student pilot is sitting there struggling with the whizz wheel. Guaranteed within 10 mins the two of them will be hunched over a chart the student enthralled not noticing the smell of wee and will come out of it know everything you need to know about flight planning. CFI will be standing by thinking how dare that old bugger instruct my student he isn't even qualified. Then after a couple more lessons thinks hells bells this kid understands flight planning and NAV.
Real instructors never have to tell people they are instructors they already know. And the main problem with the training industry/ aviation career ladder is that many many none instructors have the tick in the box and the title "instructor". The fact that students eventually reach the required standard is more a case of the students ability to learn than the instructors ability to instruct.
I actually quite like the FAA gold seal CFI system. Only ever flew with 2 of them one doing twin training and the other a BFR. It was like chalk and cheese in comparison to the other FAA instructors I had sat next to. Top system and I wish we had it in the UK.