If you are designing a complex or long workflow using SharePoint Designer 2010 and for some reason during debugging process you may want to comment out certain actions or disable certain actions. I could not find any out of the box solution to this. I am not a big fan of SPD workflow but if I write a workflow in SPD I usually put IF condition around the actions that I want to comment out and if I want to run those actions my condition will be
If 1 equals 1
and if I dont want them to run then my condition will be
If 1 equals 2
Simple.!!