nitpicking

nitpicking

An act or instance of pointing out or complaining about every flaw that one comes across (in or about something), no matter how small, petty, or insignificant. Sometimes hyphenated. You might disregard my points as just nitpicking, but you'll appreciate it when you get an A+ on this paper. This is why I hate going to the movies with you. Instead of just enjoying what we watch, you spend the whole time nit-picking!
Farlex Dictionary of Idioms.

nit-picking

n. too much minor criticism; overly particular criticism; nagging. Enough nit-picking! What are the major problems?
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • nit-picking
  • nitpicker
  • nit-picker
  • picker
  • pickers
  • one or two
  • great oaks from little acorns grow
  • Great oaks from little acorns grow, and Mighty oaks from little ...
  • great/tall oaks from little acorns grow
  • mighty oaks from little acorns grow