I'm not worried about losing our place as a 'world leader'. It's bullshit.
I'm not worried about financial institutions decamping en masse from London to Paris, Frankfurt etc. God knows I've been complaining all my life about the city's unbalancing effect on our economy.
I'm not worried about being unable to rejoin the EU because of the Euro/Schengen, I'd be quite happy with the Norway option. There are good things the EU want to do that the UK's been blocking.
I'm sad about leaving the EU for cultural/social reasons, not economic ones. I know it will reduce economic growth, but aren't we going to have to do that anyway, climate change again? It doesn't follow that we'll have to cut public services, that will still be a political choice. Education and health spending boost GDP and shouldn't be dependant on it.
the Gross National Product includes air pollution, ambulances to clear our highways from carnage. It counts special locks for our doors and jails for the people who break them. The Gross National Product includes the destruction of the redwoods and the death of Lake Superior. It grows with the production of napalm and missles and nuclear warheads.... It includes... the broadcasting of television programs which glorify violence to sell goods to our children. And if the Gross National Product includes all this, there is much that it does not comprehend. It does not allow for the health of our families, the quality of their education, or the joy of their play. It is indifferent to the decency of our factories and the safety of our streets alike. It does not include the beauty of our poetry, or the strength of our marriages, the intelligence of our public debate or the integrity of our public officials... the Gross National Product measures neither our wit nor our courage, neither our wisdom nor our learning, neither our compassion nor our devotion to our country. It measures everything, in short, except that which makes life worthwhile, and it can tell us everything about America -- except whether we are proud to be Americans.