Re: Beards, color of:
Mine started turning grey in my mid 20s.
Could be related to me doing the electricians equivalent of deleting production DBs. I've drilled through the comms cable to payment terminals during opening hours. I've run over a copper gas line with a scissor lift. And yes, I've cut live 230V cables with hand tools.
That sinking feeling in your stomach you get immediately after doing something bad - it's universal across professions.
Thankfully, I've never fucked anything major up, and I've had my hands in hospitals, power plants, ISP fiber backbones, police stations and whatnot.