Most people can list what went badly today without pausing. Ask for one thing they did well and the sentence arrives with a discount attached: it was easy, anyone could have, it was mostly luck, it still is not finished. This theme asks for the sentence without the discount.
Pick one real thing from the last day and write it down as a fact. Not that you think you handled the call reasonably well, but what you did: you took the call, you found the invoice, you said the number out loud, the customer stopped shouting. Facts are harder to argue with than praise, which is exactly why the plain version works better than a compliment you do not believe.
Then write, if you can, the part that was actually yours, the judgement, the preparation, the patience nobody saw. Luck is real and deserves naming when it was there, but people who rush to credit luck usually skip the twenty minutes of thinking that made the lucky break usable. That is the part worth keeping, because it will still be yours tomorrow.