When I said close I meant minimize. 
Some programs do not work that way, for example, even in word if I have multiple word documents open clicking on the taskbar does not quick minimize, even clicking on one of the quick view windows will not close it for me (unless I have something weird set in windows that is dissalowing this).
The way I work (and I imagine most people nowadays work this way) I often times have dozens of windows open and finding the exact program on the taskbar to minimize can take longer than just sliding the program offscreen or clicking the minimize button. I will often times slide because if I have several word documents open finding which exact one in the taskbar list will take longer.
I do realize I do things the hard way sometimes.
Edit: I shoudl have mentioned I stack application in the taskbar - I could probably change this behavior and then the quick minimize might work but then I'd pull what's left of my hair out trying to find things. 