Recently, Nick Farrell blogged on why he believes magical rituals fail. Whether you agree with it or not I think you will find it interesting.
One aspect that is not mentioned there is that it assumes magick works. I agree. Therefore, if it doesn't work, there must be a reason. If you worked by yourself, you were obviously at fault for the failure. If you worked with a group, you or someone else, or perhaps several people were at fault for the behavior.
Understanding magickal theory and then analyzing what happened during and following a failed ritual is certainly important. However, saying that you or someone was at fault for the failure is ultimately not only useless, it can also