What's missing?

I used to have a rule when I worked in factories that there should be no spare tables.
Why? Because as soon as anybody puts a table in a place, people will start putting things on it rather than putting them away. 
As you can see, I don't practice what I used to preach 'cuz the top of this drawer-set in the garage has all sorts of shite on it.
Just like the puzzles we used to do as kids, can you spot what's missing in the second photo?
Go on, it's very easy.

Ah well. Until tomorrow....