The phrase “pick your battles” is often bandied about by parents, especially by those who practice some form of gentle parenting. It refers to the fact that you should be willing to participate in give and take, saving absolutes for situations when you really aren’t willing to budge and being more flexible the rest of the time. If your life is a series of battles, you are living a war, which isn’t enjoyable for anyone. The concept is there. However, since our words hold so much power in how we think, we should really throw the entire phrase out. Viewing any interaction with another person as a battle is going to set up the situation in a negative light. Instead, we should look at each of these situations as exercises in effective communication. People do better when they are in a positive frame of mind. The same can be said for parenting.
living peacefully with children 
I agree! We can help build a much more peaceful relationship with our children simply by changing our perspective on terminology like “effective communication” instead of “battles”. I am just as guilty of using this term with other adults and I’ll be making a conscious effort to choose different wording.
I totally agree. So many people see the world ‘out there’ as a violent warlike place for which they either have to harden or protect their children. If instead we would see confrontations as a constructive thing, from which we could be able to learn, it might have very different outcomes.