I know what you did last summer
I am citizen 7264354846, pilot 29457578, authorised to enter Airport 18367464, treated in hospital as patient 304955678, with car insurance 5069274, with supermarket club card 6079783, internet broadband customer 444648945
If I buy a lot of alcohol for a party on club card 6079783, it does not cause my boss to think I'm a drunk and unfit to be pilot 29457578. If my car is CCTV'd near an 'incident' (5069274 cross linked to address cross linked to citizen ID 7264354846) it will not affect my security clearance for the airport. Nobody can analyse my club card purchase list to see if I buy Halal or Kosher food, and so it will not affect my security clearance as a potential subversive. The car insurance company doesn't know if I fly long haul and so cannot bump up my insurance as potentially tired. The hospital doesn't know if I buy sweet things at the supermarket, despite my doctor saying no sweet things.
I am citizen 555333222, pilot 555333222, authorised to enter Airport 555333222, treated in hospital as patient 555333222, with car insurance 555333222, with supermarket club card 555333222 broadband customer 555333222.
I dare not even search for information on 'dementia' in case some Jacqui Stasi goon in GCHQ thinks that *I* have dementia and a risk as a pilot. I avoid Halal meals because it might affect my security rating. I get my wife to buy alcohol because I don't want it affecting my insurance. I wait till I'm far abroad before going to see a doctor about any illness, that might affect my pilot's license, security clearance, car insurance. I check the news about anti-government protests, because I don't to be pulled in on a police trawl which would destroy my career. I am very careful who I call, where I surf, who I email, ... I am afraid of what data mining equations may label me as. I am afraid.