So, I'm settling into a new user account on my sister's computer while mine's getting its case fixed.  A couple minutes ago, I realize that I should put Scrivener on my Dock.  But I don't want to go into the Applications folder and find it.

So instead, I pull up Quicksilver, intending to open Scrivener and pin it to the Dock while it's open.  I call up Scrivener in the direct object field and I'm just about to hit Enter when I think, "Wait a second..."

Hand to the trackpad.  I grab the Scrivener icon and drag it down to the Dock—which separates to indicate I can drop it right there.

In summary: I love the Mac's ubiquitous drag-and-drop.