(Note: I think this is new in Yosemite, as I never had this problem before updating, but it's possible I just never noticed.)
In Accessibility preferences (formerly Mouse/Trackpad), it is possible to set how much time delay can occur between the two components of a double-click.
It seems OS X also allows a certain amount of cursor movement in this interval (~15 pixels, I think), and I would like to decrease the allowance to about 2 pixels.
Why? I am fairly fast with the mouse, and even at the minimum delay time, sometimes when rapidly clicking several things in a list OS X thinks I'm double-clicking on one item and opens it instead.
If you haven't experienced this, try increasing the delay in Accessibility > Mouse & Trackpad and clicking on two adjacent items in the Finder.