|This page in a nutshell: Don't get frustrated over a dispute. Get over it and move on.|
After it has been determined, often through multiple processes, that a certain result will stand, it makes no sense to continue fighting. Editors feeling the need to continue fighting after the result has been settled need to get over it and work together to improve the encyclopedia.
Don't become a Crusader
Not everyone "gets over it", though. You may feel frustrated in a short-term sense, because you "lost that round". Or, you might have a deep sense that your beliefs or views on a certain matter are the best way of improving the Wikipedia project. You do not view yourself as a dark-cloaked rabble-rouser, but rather as a noble, good faith crusader for justice.
As an editor, if you feel a strong need to continue "fighting the battle", you may feel inspired by the various great crusaders throughout history. The problem with becoming a Wikipedia Crusader Against Injustice, though, is that you may find that your online efforts to go head-to-head with the entire Wikipedia system may cause a lot of real-world grief for you, in terms of stress and anxiety.
Rather than becoming a Crusader Against Injustice and trying to take on the whole Wikipedia system, and causing yourself to get stomach ulcers, sleepless nights, and migraine headaches, you might wish to try some of these options:
The Ukulele option
If you really feel that the Wikipedia system or a dominant group of admins or the attitudes of certain other editors makes it impossible for you to continue on at Wikipedia, you might want to consider a WikiBreak. Go offline, and do non-Wiki activities such as rollerskating, tap-dancing, or ukulele lessons. Or ask that cute person sitting alone at the coffee shop out to a movie...
Swiss Family Robinson option
If you were getting into a huge disagreement with the editors in the Film Project page or the Actors Notability Guideline page, perhaps it is time to "walk away" from the whole film/movies area. Be like the Swiss Family Robinson, and go to an uncharted realm of Wikipedia where all there are is stub articles and "start-class" articles, and write articles, set up categories, and build a new world.
Lord of your Domain Name option
Or perhaps the Wikipedia model and structure is not a good fit for you. There are other non-Wikipedia Wiki-style projects with different rules and different cultures. If you want to get totally away from having to deal with other people's rules and restrictions, starting your own website or blog might be a much more satisfying option. On your own blog, there are no admins, no ArbCom, and no policies. You are the Lord of your Domain.
Throughout the last century, there have been individuals who have, at a great personal cost, waged one-man or one-woman battles against huge organizations and systems, because those individuals believed that there were important values at stake. Just to give one example, in the 1960s, civil rights activists in the US protested against discriminatory practices in a number of US states. Should those activists, after a state-level court ruled that "Whites Only" theaters or beaches were not in violation of the law, have just decided to "get over it", and accept the status quo? It can be argued that in some cases, some of the civil rights activists did a great service to society when they continued to battle for their cause, and appeal their cases up to the Supreme Court. Their protests and court challenges led to the removal of official, state-sanctioned discrimination throughout the US, when the Supreme Court struck down state-level discriminatory laws as unconstitutional.
These activists were viewed, at the time, by certain sectors as troublemakers who were disrupting the established order of society. Just as today, some Wikipedia editors view fellow editors who wish to continue battling for a certain policy or guideline—even after a Committee or board has ruled against them—to be "troublesome" or "disruptive". However, so long as the activists in question are using civil behaviour, legitimate channels and a good faith approach to raise their concerns, and not going to the "dark side" of WikiHate, bad faith, and disruption/flaming, it can be argued that these individuals serve a purpose. It could be argued that "good faith", clean-fighting crusaders for policy changes and guideline modifications are like modern-day version of Socrates; they are gadflies who raise concerns about the system and call for reforms. We should accept them, then, rather than pushing a cup of poison Hemlock towards them.