Imagine that you spent your entire life on this earth as a professional musician, and a good one, too ... let's say you played the piano, organ, and accordion, appeared in many public venues, and taught many students.
Imagine that your assignment one day was to begin teaching the organ to a 13-year old boy with no prior musical training whatsoever, from the very beginning, not knowing if he had any musical ability at all.
You're given a little spinet electronic analog organ with 2 split manuals and 13 stub pedals on which to give him his lessons.
You discovered, rather quickly, that he had some talent, and he spent nearly 3 years with you, learning a great deal.
After that, you lost contact with him, and you moved away from the area to a place where he didn't know how to reach you any more.
The time you spent with him then faded into a memory.
You never found out if he ever continued his playing, or if he ever gave it up.
You never saw him again.
Over half a century elapsed, and, after living a nice, long life, you passed away.
You never found out, while you were still on this earth, that this same young boy you taught from scratch not only continued playing the organ, but he went on to play for large crowds of worshipers, reached thousands of people with his playing, and even wrote a number of works for the organ the year after you died.
You never found out that he never forgot you, that he wrote some fine, original music for the instrument, or that he dedicated one of those pieces to your memory.
You left this world before you could ever hear it performed.
But the fact that you made such a difference in the life of that one boy, that you left your mark upon him, was worth all the effort you ever put forth to be a teacher.
The proof is there, we may not live to see it or hear it, but the time we spend with a child is never wasted.
That boy ... was me.