Electricity - 'live' and 'neutral'

I have often wondered why electric plugs has a 'live' and 'neutral' connections and you are strictly supposed to wire the live wire to the live connection and neutral to neutral. I have long suspected that this is nonsense. After all we know that + and - in electricity is just a convention. In basic physics you are taught that current flows from + to -. Later on you find out than in a wire the current is electrons, and they actually 'flow' from - to +. Anyway mains electricity is alternating, its not flowing anywhere its just vibrating backwards and forwards 50 times a second.

Recently I have been changing quite a lot of plugs from British to German.  German plugs only have two prongs and you can put either prong in either hole. They do have a live connection and a neutral one but you can turn the plug over

to connect them the wrong way round. All my rewired appliances work fine. Even the fan heater. (I dont know if the fan goes backwards!)

I am staying with David and he had a theory that you couldn't be electrocuted by the neutral wire. He has a screwdriver which, he says, lights up when you touch the live but not when you touch the neutral. It seemed to do that but I didn't believe it. So we unscrewed the socket from the wall and I touched live then neutral in turn. I was wearing socks. They BOTH gave me mild electric shocks. David didn't dare do it without his rubber soled shoes on.

CONCLUSION: It doesn't matter whether you wire live to live or live to neutral. You can forget the stupid colours. (But do remember to wire the nice green and yellow one to earth!)