Wish I'd followed up ideas for fire stopping and intumescent collars for wiring and openings in fire doors, ducts and between compartment walls and floors in flats in the early 80s.... would have been very comfortably off now.
Oh God, I thought of take apart displays and lighting for trade shows in the early '80's, thought of a proximity switch to to be worn and alert parents if their kid wandered away, years before "bogeymen" were news. Designed a one side bracket for electrical cable trays, so that getting pipes and cables in and out was far easier, couldn't be arsed doing anything and a decade or so later a French firm did.
Accy, thanks but I was lucky, once my company was ahead of the game, by miles, instead of consolidating, I fannied about cycling until everybody else had caught up, then taken over. I'm just not motivated by money, I am scatterbrained, I lose total interest once I've got a business up and running that's why I've lost 2 of them, wish I'd had a really straight, sensible and dreary partner to deal with details. Too late now.