Firefighter - I'd be so scared of them being killed every time they left for work.
Police - same reason as above re worrying about them every day.
Teacher - I'm a teacher and, whenever I'm with teacher friends, 75% of the chat seems to be school related. Couldn't do that in a relationship.
Armed Forces - too much moving around and no control over where you get sent when.
Foreign Office - wouldn't want to live abroad for a long period of time.
Warehouse work/cleaner/retail assistant - probably don't earn enough money to help support a family and I'm not exactly earning a fortune so I couldn't afford to be with someone earning minimum wage. And - huge snob alert - I'm not sure I'd have much in common with most in these lines of work.
Fishmonger or Butcher - I can't cope with the smell of raw fish or the thought of raw red meat.
Immam/Rabbi etc - I'm a Christian so our beliefs wouldn't be compatible.
Politicians from political parties I don't support - our beliefs and principles wouldn't be compatible.
Racing Driver/BMX Racer/Extreme Sports Athlete - I'd fear for their lives too often.
Any Computing based profession - I find it confusing and boring and would want to ban AI. I tend to find IT professionals slightly confusing and boring too.
Psychiatrist - I'm officially crazy so I'd feel constantly diagnosed and analysed.
Pilot/Flight Attendant - I'm terrified of flying. I assume they'd want to travel a lot and, although I love travelling, flying is an absolute last resort for me if there's no other possible way of getting somewhere. And I'd be scared of them crashing every day.
Funnily enough, I'm single 😛