I agree with the vast majority of whats already been said, especially about the numbers of varied reasons.
One other thing that ive given a lot of thought to, is timing. Not seasonally, or patterns, just good old fashioned timing...you know...fella walks in and sits down, waits 2 min. and game comes walking by. There are fellas, that just have good luck in their timing, and though we'd all like to think we are somewhat in control of the hunt, it all comes down to timing, that essentially, is out of our control. We can be there when we THINK game should be moving by, but we are at the mercy of life's timing, and that so often goes against our planning and desires. For instance, "If I didnt have to stop and air up my truck tire, I would have been on stand and killed that ol mossy horned buck, that im now watching from 100 yards away, going right past my stand"...kind of timing. Some guys just have better timing.