Nit Picking

http://en.wikipedia.org/wiki/Nitpicking
Excerpt:
Nitpicking is the act of removing nits (the eggs of lice, generally head lice) from the host's hair. As the nits are cemented to individual hairs, they cannot be removed with most lice combs and, before modern chemical methods were invented, the only options were to shave all the host's hair or to pick them free one by one.
This is a slow and laborious process, as the root of each individual hair must be examined for infestation. It was largely abandoned as modern chemical methods became available; however, as lice populations can and do develop resistance, manual nitpicking is still often necessary.
As nitpicking inherently requires fastidious, meticulous attention to detail, the term has become appropriated to describe the practice of meticulously searching for minor, even trivial errors in detail (often referred to as "nits" as well), and then criticising them
(see nitpicking (pastime)).
Excerpt:
Nitpicking is the pastime of pointing out minor flaws or mistakes. The term is often used in a negative light. The term comes from the intense concentration and careful attention to detail required when nitpicking (searching for the eggs of lice, known as nits).

[edit] Film and television

Some nitpickers specialize in finding mistakes in movies and television shows. These mistakes can range from very trivial mistakes that regular viewers don't notice, to very serious mistakes which disrupt the suspension of disbelief in the show's story for even casual viewers. The types of mistakes include inconsistencies or even contradictions between episodes in a series,^[1] to plot devices and oversights, to production problems.^[2]
Nitpickers will also be inclined to find trivia in a show, including possible "inside jokes" and "signature items" added by the writers or other members of the production team.
When a recurring signature item is found in a series (such as the occurrence of the number 47 in Star Trek), nitpickers will often pore over the episodes with great diligence to find all the occurrences.
Books have been published on the subject, such as The Nitpicker's Guide for X-Philes (for fans of The X-Files) by Phil Farrand. Farrand started with four books nitpicking Star Trek and a couple^[quantify] of its spinoff series^[which?].^[3] Since the beginning, Farrand has emphasized that nitpicking should be done "with good cheer."^{[citation needed]}