I share my talents and skills with humanity.

Humanity is not a size anyone can actually give to. What arrives instead is one person at a time, usually at an inconvenient moment.

Somebody behind a hardware counter spends twenty minutes drawing a valve on the back of a receipt, for a customer buying nothing that day. That isn't service to the species. It's answering a question properly, at the cost of twenty minutes he didn't have.

Skills kept in one head die there.

The handing-over is unglamorous — it happens in stockrooms and car parks and kitchens — and it is the whole mechanism by which anything useful outlives the person who learned it.