1) I think it is totally possible that small scale effects can bug you at different layers of your neural processing: just because it is extremely difficult for

1) I think it is totally possible that small scale effects can bug you at different layers of your neural processing: just because it is extremely difficult for me to perceive a sound doesn't mean my ears aren't being affected by it and even providing a signal to my brain with the information where it is being discarded actively. 2) They often don't? A lot of LEDs flicker at something like 60Hz. Sure: if you stare at the light you might not notice it blinking, due to the limitations of the sensors in your eyes that can weirdly "get tired" of looking at the same thing for too long, but if you move your eyes across the light quickly you will see it blinking as now you are getting a broken dotted line carved into your vision. I find this maddening when there are such lights in my peripheral vision.