I was born a Quaker, although it took many, many years before I realized there was a name for it and that there was an organized group of like-minded people.
1) Peace and Non-Violence - Many Quakers find this to be one of the most important things about being a Quaker. The Peace Testimony is the belief that war is wrong, as is any form of violence. As a follower of Christ, I find it hard to combine Jesus' teachings with Constantine's "Just War" theory. Christ never advocated any form of violence; righteous anger, yes - violence, no. I've had people try to convince me that there is a time for war and use the Old Testament as explanation. I don't buy it, especially since most of these people discount almost everything else that was commanded in the Old Testament. Further, as Jesus is described as the "Prince of Peace," how can that be combined with war? I believe that when we delve into history, for every example of war, even what has been described as a just war, we can point to past violence as the cause of that war. Violence breeds violence, not peace.
2) Simplicity - The Quakers believe in living a simple life. They once donned unique clothing, such as that worn by the Amish and some Mennonites; however, most came to believe that wearing clothing that set them apart actually drew attention to them. The belief in simple living stems from the belief that people should spend their time and energy focusing of what is important rather than on things they consider frivolous. The old-fashioned dress became something frivolous that detracted from truly important matters.
3) Equality - Quakers were actively involved in both the abolition movement and the early women's rights movement. Male and female, black and white (and all other races), all are considered equal in the eyes of God within Quakerism (also known as the Religious Society of Friends). Early Friends had no problem accepting women as church leaders. They were also instrumental in mental hospital and prison reform. In the early days, Quaker men refused to remove their hats when greeting others, especially those of a higher social station, as they felt this was an indication that one person was superior to another.
4) Sacred Life - Quakers hold a number of beliefs that seem unusual to outsiders until you consider this very basic concept. As a general rule, Quakers do not practice baptism or communion as they believe we have inward holy experiences that occur in everyday life that do not need to be represented by physical ceremonies. They consider baptism to occur as an inward experience and that every meal is a form of communion. Further, Quakers often will not swear an oath as they believe the truth is something that should permeate our lives and that we should not change our behavior just because we swear to do so. Often days that are considered holy by other Christians are not observed as they consider every day to be sacred; no one day should be singled out as special.
Essentially, Friends believe that everyday life is sacred and that we should not behave differently just because a certain time is designated as special. For instance, Lent is usually not observed because of the belief that it is wrong to fast part of the time, and then to be gluttonous the rest of the year. This belief that everything is sacred extends to the belief in equality (no one person is above another) and to the peace testimony (violence harms people whom God loves), and even in eliminating unnecessary distractions from one's life (unnecessary attention to man-made things).
Friends don't just believe, they act. Although the denomination is a very small one, members have been instrumental in founding organizations such as Greenpeace, Oxfam, Amnesty International, and the Christian Peacemaker Teams. In 1947, the Religious Society of Friends won the Nobel Peace Prize.
Even though I am a Quaker, I was a member of the United Methodist Church for many years and still find much of the official doctrine appealing and enjoy many of its traditions. For instance, I enjoy attending Ash Wednesday services at a Methodist church as I love the beauty of the imposition of ashes and the idea that Methodists (and other Christians around the world) are participating in that ritual. And some of my best memories are of our children participating in the Christmas Eve services at our church in Florida. I feel that enjoying these traditions does not conflict with my Quaker beliefs because, although I find personal inspiration from the rituals of the various branches of the Church, I do not find them necessary.