Suppose you went to a shooting range and were handed a rifle that you had never shot before.
You are shooting at a target that is one-hundred yards away and you are using iron sights. Your partner is watching the target through the spotting scope so you can make adjustments to the sights.
In one case the only information he gives you is "Miss. Miss. Miss...."
In the second case the information he gives you is "Missed high-and-to-the-right. Missed high-and-to-the-left"
In the third case the information he gives you is "You missed and are eight inches high and a half inch to the right."
Who do you think will converge to a usable setting first?
Be sure to provide the details of what when well
It is just as important to include the things that were done well. Consider when a new girlfriend invites you over for a home-cooked meal.
The temperature of the food and the room was perfect. The plates and silverware were clean and the candles were elegant. She served pot-roast, salt roasted potatoes and your favorite pie. The coffee was fresh and the wine was a rare treat. She was attentive and laughed at all of your stories.
What would many guys tell her?
"I hate cauliflower." or "The wine glasses weren't the right ones for a 2011 Estate bottled Nebbiolo." perhaps "Bach's Ave Maria is not my favorite music."
Those kinds of responses are eviscerating and greatly diminish the chances of her ever feeding you again.
Much better to emphasize the things that she did well. She is much more likely to replicate the things that you tell her were "perfect".