I was recently reminded of Amara’s “Law”, an adage by American scientist and futurist Roy Amara on the challenges of forecasting the effects of technology; in particular, encouraging people to think about the long-term impact of technology:
We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run.
Roy Charles Amara (1925-2007)
It might be best illustrated by Gartner’s popularised hype cycle, characterised by the “peak of inflated expectations” followed by the “trough of disillusionment”. For example, see: artificial intelligence, virtual reality, autonomous vehicles, blockchain, etc…
Digital, Data & Policy 
And the daddy of them all controlled nuclear fusion… still 30 years away.
On AVs… a few days ago on a single track rural road I came up behind a chap with a long trailer behind his car. On the left a few yards behind him was a field gate set back a few feet and open. I stopped short of the field gate because I deduced that he wanted to back into it. How would an AV deduce that ? If it didn’t and it stopped close behind him how would he have extricated himself from the situation? Will we be able to shout “back up you fool” to an AV and have it obey? I’m assuming said AV is returning empty from delivering a passenger or its a Level 5 AV with no human operated controls and is locked.