I cannot recall where I came across this quotation, “when you have achieved a victory, tighten the strings on your helmet”.
But I take it to mean that the time you are most vulnerable and in danger of doing something stupid is when things are going well.
I have always been of this view, and first discovered it in the sporting arena. Then, it became apparent that the same lesson against complacency, overconfidence and developing hubris in my ordinary life, including work was clearly identifiable.
I could not have put it so eloquently but I fully subscribe to the sentiment.
In my own plain words, “when things are going well, be careful”.