One of the reasons I went macro is because waiting for the rut to ripen--affording a priceless shot of a big buck--can be a tiring excercise in patience. So rather than loom over the pot, waiting for it to boil, I've lost myself in the tiny worlds that normally fall under foot.
My own personal superstition also tells me that the bigger the distraction out in the field, the bigger the buck will be when I peer up from obsessing over a blade of grass. This phenomena was beautifully depicted in one of my favorite films, Never Cry Wolf, when the main character has his first, meaningful, wolf encounter after he's completely immersed himself in photographing a wildflower.
When this phenomena doesn't work, and you miss the shot, it's Murphy's Law.