Personally I think “instincts” are very analytical and not out of the blue hunches.  By playing thousands of tournaments and hundreds of thousands of hands, you subconsciously register and connect betting and timing patterns with hands.  So when a circumstance comes up where you say, “that feels like AK” it's because the circumstances of his play have triggered something in your mind that remembers those actions to frequently be connected with AK(at least this is what i believe, i don't have a PHD in neuroscience).  So i think your instincts are a very important part of choosing what action to take.  An example, recently I was somewhat deep in a turbo tourney, the action folded to the SB who was a very tight player.  He very quickly made it 4x.  I was in the BB with 33, and a 25bb stack i believe, perfect for the reshove.  I dragged the bar all the way to the right, hovered my mouse over the button, but something didn't add up in my mind, so i swallowed my medicine and folded (but hated it).  I hated it less when he showed me TT.  Folding there was definitely the pivotal hand of the tournament.