Meaning: To be kidding oneself, to be wrong
Literal translation: To stick one’s finger in one’s eye
Synonymous expression :se mettre le doigt dans l’œil
Notes: The French expression se fourrer le doigt dans l’œil offers a great visual image, but the logic behind it is less clear. Does the finger you’ve accidentally stuck in your eye make you unable to see the mistake you’re making (because the finger is obscuring your vision), or is the finger actually damaging your eye, which would impair your eyesight permanently? And is the speaker claiming that you don’t know your finger is there, and therefore that you’re kidding yourself in thinking that what you see with your obscured vision is the whole picture?