I was thinking today about the way Middle Son wants everything to be Just So.
As a toddler he would drink a bottle before we put him to sleep. He noticed that we always put the bottle in the sink when he was done. So he started putting it in the sink himself. Even when he was so tired he could barely stand up, he would still get up, run over to the sink, and toss the bottle in. Sometimes he would drop the bottle and it would roll under the TV where he couldn't reach it. Then all hell would break loose as he tried to grab it and couldn't.
I have magnetic child-proof locks on my kitchen cabinets, and I have four magnets that go with them. After I use a magnet to unlock a cabinet, I stick it to the hinge of the cabinet.
Then Middle comes in, grabs the magnets, and lines them all up in a perfect vertical row on the side of the refrigerator.