bee in one's bonnet

a bee in (one's) bonnet

An obsession, often with something that is strange or a source of agitation. Ever since the blizzard last year, Dad has had a bee in his bonnet about moving to a warmer climate. It seems that Mike still has a bee in his bonnet over the criticism he got in the staff meeting.
See also: bee, bonnet
Farlex Dictionary of Idioms.

bee in one's bonnet

A strange idea or notion; also, an idea that is harped on, an obsession. For example, Bill's got a bee in his bonnet about burglars; he's always imagining strange noises. This term, which replaced the earlier have bees in one's head, transfers the buzzing of a bee inside one's hat to a weird idea in one's head. [Second half of 1600s]
See also: bee, bonnet
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • bee in bonnet
  • bonnet
  • a bee in (one's) bonnet
  • a bee in bonnet
  • have a bee in (one's) bonnet
  • have a bee in your bonnet
  • get worked up about (something)
  • get worked up over (something)
  • be (as) busy as a bee
  • (as) busy as a bee