Artificial intellegience.......from luxury to uncomfortability

One thing is for sure, AI would change the existing world. a technological bloom which crosses all limits.......a technological revolution never seen before by mankind....siri , face recognition , self driven cars are just the beginning.......it's narrow or controlled AI.....once the algorithms are out there running in their full capacity in every field....and once IoT is practically applicable.....that is every thing surrounding us becomes a machine connected to internet.....the change would be huge......Artificial intelligence outperforming humans.....
AI would be active in all the fields....bussiness , law, economics, trade....taking over everything because of fast processing than the human brain...but what if the system AI is working on is hacked or your laptop malfunctions or crashes.....the main objective is to keep all the working of AI in human hands........from cars control to nuclear warhead launching.....

NOW HOW IS AI DANGEROUS!!!!!!!!!

What about the mass unemployment ......computers performing every task....what would we humans be doing.....even chauffers and uber drivers would be unemployed....
what if some one with an evil intention programs it for destruction.....
what if it performs a beneficial task by taking a destructive route...it's no human that it would think or feel.....
it's not that just laymen are fearing AI.....stephen hawkingss, bill gates, elon musk and likes are also fearing AI....

So concluding AI and machine learning topic....What I feel is, we are on the verge of a technological revolution ,...what we need to take care of is.......It ultimate control should be with the humans....