Try this test:
Take something you are in the habit of looking at very often, but in a subconscious way, and move it.
Our kitchen clock literally fell off the wall the other day and is now residing on the counter next to the coffee machine until I can its frame back together. I knew that I look at that clock often (is it time for the kids to go to school? How much longer until the noodles are ready?), but until it fell off the wall I had no idea how often. Now when my eyes are drawn to that empty patch of wall, I NOTICE.
I thought I might look at that clock about a dozen times a day, but now I realize I look at that thing all the time. It has become an unconscious habit, and I wonder, if an obsessive one.