I think there is a subtle link between comfort and boredom. If I'm not completely at ease and comfortable, I notice I begin to fidget around. My attention gets diverted from a hunting focus to one of finding comfort, often subconsciously. I sit, I stand up, I stretch, all bad things to do when hunting on the ground. During these restless times there is a chance I've spooked some animals and did not know it.
So, during the past several years I've gone after 'chairs' or other devices that allow me to sit in complete comfort for several hours. Depending on terrain, my favorites are the Waldrop pack seat, Millenium blind chair, and the Hammock seat.
For me, comfort equals concentration and concentration prohibits boredom.