When I have the missing part syndrome, I soon become angry, almost a catatonic state and develop hysterical blindness.
I wish that I was joking. I get so irritated, especially when I recall seeing said part several times when I didn't need it yet.
I was looking for my compression gauge and looked through all of my tool drawers but couldn't find it. I went and bought another one. Once I settled down a few days later I found the missing one in the middle drawer on top of everything else in that drawer. It was right side up so I could read the dial!!!