You can't fight every battle you encounter in life if you want to keep your sanity. Sometimes you have to let things go, but how do you decide which battles are worth fighting?
The Consumerist offers an example of a battle not worth fighting:
Back in 2008, a couple in Olde Fairhaven, Virginia put up a sign in their lawn showing their support for a presidential candidate. This simple action led to a feud that has raged for years and cost the neighbourhood homeowners association hundreds of thousands of dollars. Now the HOA is broke, and the central "town square" that turns a clump of townhouses into something resembling a community is up for sale.
This all happened because the homeowners association decided to enact a little revenge against the couple and their lawn sign. This offers at least one good piece of advice: don't choose to fight a battle if you're simply feeling bitter.