“I failed” and “I tried something hard” can describe the same day. Pick the true one that helps.

Two accurate descriptions of the same afternoon can send you into completely different weeks. One tells you what happened and stops; the other tells you what happened and leaves a door open. Choosing between them is not lying to yourself, provided both are true.

After something goes badly, write the sentence you have been repeating in your head, then write the other true version underneath it. Pick whichever one you could act on tomorrow, and use that one when somebody asks how it went.