There are many things that OS X does well, and a few things that it could do better. One area of potential weakness is window management, and that's where Flexiglass comes in.
Flexiglass, a US$7.99 (currently 20% off) app from the Mac App Store, adds to and enhances the built-in window management features of OS X. It allows you to quickly resize and move a window using any part of said window when a modifier key is held down (the Option key by default), not just the title bar or the resize corner. With the modifier key, a left click and drag allows you to move the window, while a right click resizes the window, altering its size from the bottom or right hand-side edges. If on a trackpad, one, two or three-finger mousing does the same. The result is a fast and efficient means of window movement and resizing that doesn't get in the way of normal operations.
Flexiglass also allows you to move and resize windows to set positions like full screen, half screen horizontally or vertically by dragging the window to the edges of the screen or through keyboard shortcuts. An option to double click the title bar or right click the green zoom button to maximize a window is also included, while a right click on the red button will quit the program, not just close the window.
Flexiglass rolls in many features found in other separate apps, with lots of options to enable or disable features that you don't want. It's a fast, slick experience that caters to keyboard and mouse jockeys alike, so it's well worth considering if you find OS X lacking in the window management department.