I just stood up from my computer, and discovered that the tensile strength of the cords for my my semi-expensive headphones is less than the resistive friction of the 3.5" headphone jack.
By this, I mean that I snapped my headphone cords (earpiece and microphone) right there, the headphones coming with me and the jacks plugged firmly in the front of my computer.
This really sucks, and I'm frustrated to have now cost myself the price of a new pair of headphones (or, repair time). But what really smarts about this is that the problem of tearing-plugged-in-computer-cords is a solved problem.
Remember this guy? The MagSafe power adapter, which keeps you from breaking your wall adapter/the power cord/your MacBook's power socket?
THIS IS HOW HEADPHONES SHOULD CONNECT