Se mettre le doigt dans l’oeil

Le mot du jour : Se mettre le doigt dans l’oeil.
This is a painful expression 😀

“Se mettre le doigt dans l’oeil” means to put your finger in your own eye, not something very nice when it happens!

The signification is to get something completely wrong, or to kid yourself.

Ex : “S’il pense que le problème est réglé, il se met le doigt dans l’oeil !” (If he thinks the problem is solved, he is completely deluded)

I am not sure about the origin of that expression, but I can understand how poking your eye by mistake can be considered a big error!