hobby horse vs neurosis

hobby horse

noun
  • A topic about which someone loves to talk at great length. 

  • A child's toy consisting of a (usually wooden or cloth) horse's head mounted on a stick. 

  • The Irish hobby, an extinct breed of horse. 

  • A puppet-like costume used in some traditional dances and festivals that gives its wearer the appearance of a man on horseback. 

  • An early bicycle with no pedals or brakes; a draisienne. 

neurosis

noun
  • A mental disorder, less severe than psychosis, marked by anxiety or fear which differ from normal measures by their intensity, which disorder results from a failure to compromise or properly adjust during the developmental stages of life, between normal human instinctual impulses and the demands of human society. 

How often have the words hobby horse and neurosis occurred in a corpus of books? (source: Google Ngram Viewer )