Related Clues:

• Head-slapper's shout
• Note that conveys annoyance
• The note C
• Cry often heard by Lisa Simpson
• 'Shoulda thought of that!'
• "Shoulda thought of that!"
• Utterance accompanying a head slap
• 'I messed up, Bart!'
• 'How could I have missed that?!'
• 'Gah!'
• Note brick-carrier brought back
• 'I'm so stupid!'
• Exclamation on 'The Simpsons'
• Head-slapping word from Homer
• 'That was stupid of me!'