Deferring to "I have a system" is indicative of one of two things:
1) you're so madly successful that you don't want to share your tricks and intentionally keep everything hush hush so that no one catches on and copies you
2 you have some occasional success with kids who are very talented and very motivated, but success is spotty at best and you're not really sure which parts of what you randomly do are successful so you make vaguely secretive comments about a "system" whose components you're incapable of articulating (possibly because there's nothing coherent to articulate)