have a bee in your bonnet
idiomPart ofbee
have a bee in your bonnet — idiom
1. to keep thinking or talking about one idea because you believe it is very import
1.idiom
Definition
to keep thinking or talking about one idea because you believe it is very important, often more important than it really is.
Example
Otis has a bee in his bonnet about cycling to work instead of driving.
Ever since the news report, Joshua has had a bee in his bonnet about food waste.