The ability to teach, to coach students from many different backgrounds to be the best they can be, to assess and build on competencies and exceptional people skills are some of the things that differentiate a great instructor from the clock-watchers and dinosaurs..
In my decades of experience (from my first job as..a flying instructor) the very worst ones are the ex airline, ATC or military ones. Sorry to say, they have a very different attitude to a Grade 3 who has a recent memory of what it is like to be in the student's seat in a little training aeroplane. Provided that Grade 3 hasn't been trained by a dinosaur and is a critical thinker.
There are great careers and many rewards in instructing if you hang in there and give yourself time to rise to the top of your game.