People write things off before testing them. How the moon effects a person is individual, and of course, it is these personal effects which truly impact one's magical working.
It has become modern practice to only pay attention to the phase of the moon, when in fact, it could be pertinent to keep a track of the astrological sign the moon is currently in. The same is also true of the sun.
Most practitioners keep a diary, in this diary a mood record should be found along with details which impact on one's practice. It could be an interesting research idea to see how the moon phase effects the mood and magical work by actually recording data from both and comparing, seeing if there is a pattern which emerges.
Many police-person or health professionals hold the belief, or rather have directly experienced, that people seem to get a little agitated towards the full moon, an excess of energy one might say. Even the etymology of the word lunatic has connections to the moon.
Whenever someone asks "Why? "How?" "What?" my response is "Well, this is what happens for me (or doesn't as the case may be), why not keep a record, research, and find out for yourself?"
Every person's experience is different and one should seek to find what works themselves, not what works for another person. So, good luck in your studies!