What does it mean when someone says "good work"?
Generally it means a good thing (unless you're being sarcastic), but have you ever stopped to ask yourself why exactly is the work that good?
I've previously written about the importance of meaningful feedback when something needs improvement, but this is also relevant for when something's well done.
"Good work" is just like saying "I love you": it's easier said than explained in detail.
My two cents on this: good work is work that actually works. How do you know if it's working as it should? By defining very well what you asked for in the first place and what your purpose is.
And still so many people ask about the importance of a carefully constructed briefing.