A monk asked the Chinese Ch'an master Chien Paling:
-What is the difference between the meaning of the Sutras and that of the Patriarch?
The master replied:
-When it is cold, hen would go up on a tree and duck down to water.
The things to watch are comparative judgments, thoughts and worries. I don't think you need to watch any in the physical world of form. I'm looking at a computer right now but it's basically empty until I employ the keyboard. Observing doesn't effect any object. If you watch from within the activity of the mind does the work of Buddha.