UK Covid.
We did some extensive planning for how to cope with a global pandemic. And then threw it away.
Covid happened. And we tried to ignore it for too long and then muddled through while exploiting it for personal gain. That went badly wrong.
The second wave happened and we deliberately forgot all the lessons from the first wave. That went badly wrong too.
We took the edge off with a vax programme. Before that had even finished we screwed it up.