This is the literal English equivalent of the German proverb
Wenn es dem Esel zu wohl ist, geht er aufs Eis tanzen
The proverb commonly describes the behaviour of people who are comfortably well-off and perhaps somewhat complacent, so they seek a little excitement in their lives by doing reckless things.
The expression was used by some posters in German forums to characterize the government's decision in 2015 to allow large numbers of migrants to enter the country.
Currently I have seen the expression used a couple of times to explain the significantly increased popularity of the Green party in Bavaria, which is the richest region of Germany and traditionally very conservative.
I have not been able to find a good English equivalent. Does anyone know of a figurative expression for complacent people who indulge in foolish behaviour in order to spice up their lives a little?