The Surprising Answer to ‘Why Didn’t I Think of That?!’ Crossword Clue

The answer to the crossword question is GREATIDEA. The clue, “‘Why didn’t I think of that?!’” suggests that the answer is a phrase that someone might say when they hear about a particularly clever or insightful idea. “Great idea” is a common expression that fits this description perfectly. The exclamation mark reinforces the notion of excitement or surprise that one might feel upon hearing about such an idea. Therefore, the answer to the crossword question is “GREATIDEA.”