Sometimes something as simple as taking the time to teach a kid how to make an E chord can set off a chain of events that changes the world.
Patrick, that's so true.
I always try to take the time to chat and listen to "new" players who will quite often come up after a gig and want to talk guitar.
As a learner I picked up lots of tips the same way and was always thrilled to be shown something new and find another doorway opening with all those new possibilities.
It maybe doesn't add up to "mentoring" as such but it could make all the difference to a young players potential.

C-flat.