Mercury represents non-emotional, rational, objective thought. Mercury is flexible, responsive, and adaptable. Part of its job is to help disburse information, so it rules perception, language, writing, editing, research, speaking and learning. Mercury also rules telecommunications, computing, software, electronic gadgets, shipping, couriers, and transportation, etc. So, it's a pretty important planet to just everyday living.
So, when Mercury goes retrograde, it scrambles information, causing static, confusion and forgetfulness. The effects are universal and all peoples feel its effect, regardless of their own signs. The signs Gemini and Virgo feel it slightly more because Mercury is their ruling planet and because they're such picky perfectionists and they really do expect their lives to go like clockwork.
Mercury Rx periods is the revealing of things hidden [past crimes are revealed or criminals located who were hiding during these times, clues are found or researched that had been previously overlooked in the past]. Also, investigations can be horribly botched during those times too. Probably it's almost instinctual when detectives review and reveal during these times.
Quote by Steven Forrest: "Mercury retrograde isn't bad; it just takes some planning to cooperate with the energies. It's meant to be spent assimilating experiences, reviewing the past, and redoing, in general. As a matter of fact, if you really want to get the most out of Mercury retrograde, confine your activities as much as possible to those that have "re" attached to the beginning of the word. Reschedule appointments, repair vehicles, return to the past, rewrite documents and agreements, and so forth."
Mercury RX is a great time for writers to go back to their work and edit. You can find more mistakes during that time, and you might also come up with ideas to spice up your writing, make it stronger. It's also a good period to clean out files, closets, return to unfinished projects and reviewing them, spend more time mentally re-viewing things that have happened in the past, get in touch with old friends, and schedule class reunions.
Some "don'ts" to get you through this period: don't start any new task or project (jobs began under a Mercury Rx period, even during a shadow period before or after, have always ended either being renegotiated usually not to our benefit or dropped altogether), don't plan any extended air flights or other lengthy trips, don't start any new medical procedures; if the appointment is for diagnostics or researching, by all means run with it and prefer to wait until after the Rx period to make major decisions.
Sometimes, however, the only thing that can be changed or have power over an unresolved issue is to change the way to deal with it: acceptance, tolerance, avoidance, or forgiveness are the only constructive outlets.