Nitpicking is a term, first used in 1956, that describes the action of giving too much attention to unimportant detail.  A person who nitpicks is termed as a nitpicker.  
The terminology originates from the common act of manually removing
nits (the eggs of lice, generally head lice) from another person's hair.
As nitpicking inherently requires fastidious attention to detail, the term has become appropriated to describe the practice of meticulously searching for minor, even trivial errors in detail.
Nitpicking has been used to describe dishonest insurers
and bullying employers, or even bullying family members. 
References [ edit ]
in Wiktionary, the free dictionary.
^ a b
"Definition of NITPICK". www.merriam-webster.com . Retrieved . 11 January 2021
"NITPICKING | meaning in the Cambridge English Dictionary". dictionary.cambridge.org . Retrieved . 10 January 2021
Dash, Rajendra Kumar (2015). . PHI Learning Pvt. Ltd. p. 336. Professional learners dictionary of spoken English ISBN . 978-81-203-5225-4
Meinking, Terri; Taplin, David; Vicaria, Maureen (2011). "27. Infestations". In Schachner, Lawrence A.; Hansen, Ronald C. (eds.). Pediatric Dermatology E-Book. Elsevier. p. 1554. ISBN . 978-0-7234-3540-2
Grove, David (2013). . Oxford University Press. p. 114. Tapeworms, Lice, and Prions: A compendium of unpleasant infections ISBN . 978-0-19-165345-2
^ Jean-Marc Bourgeon, Pierre Picard.
Fraudulent Claims and Nitpicky Insurers. cahier de recherche 2012-06. 2012
Management Bullies: The Effect on Employees. Journal of Business Studies Quarterly. 2013, Volume 4, Number 4. ISSN 2152-1034