I'm there with you and feel your pain. I know the feeling.
I built a nice bike for my nephew and found it laying in his back yard, covered with snow and the engine seized because he ran it without oil.
I packed it up, brought it home and rebuilt the top end and sold the bike.
When you build a bike you put a little of yourself in it. Seeing your work abused and neglected can really pi$$ you off. My nephew hasn't spoken to me since. So be it.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"