Life is a mixture of dark and light. The natural tendency is to categorize dark as bad and light as good, but that is matter of perspective. In Buddhism, they talk about "seeing things as they are." To see things as they are is to see that all things are simultaneously good and bad and that they are only bad or good as Shakespeare would say, "if we think it so." For me, I try and look at things as lessons. I truly believe that in life, lessons can yield good even if they are born out of bad. It is matter of perspective. The graphic above deftly explains the taiji or yin-yang symbol. There is dark and light and in that dark exists some light and in the light exists some dark and together those four things are joined together by the circle of life. When we find ourselves up against a wall and things seem like they are not working out, it is helpful and even therapeutic to try and look for the light. I know that it is hard and seems like "new-age" mumbo jumbo, but based on the taiji, one can see that in order for darkness to exist it needs light and thus light needs dark to exist as well.
Aikido is the way that it is because we choose to see light in even the darkest of situations.