have a bee in your bonnet

US /hæv ə bi ɪn jʊər ˈbɑːnɪt/
UK /hæv ə bi ɪn jʊər ˈbɑːnɪt/
"have a bee in your bonnet" picture
1.

avoir une idée fixe, avoir une obsession

to keep talking about something again and again because you think it is very important

:
She really has a bee in her bonnet about recycling.
Elle a vraiment une idée fixe sur le recyclage.
He's always got a bee in his bonnet about punctuality.
Il a toujours une idée fixe sur la ponctualité.