I've got a Microsoft Wireless Laser Mouse 6000 (oooh, big number so it must be impressive right?) because it's the only mouse I've found so far that works on my desk, which isn't anything special - just you typical laminated woodgrain top like most desks at Officeworks. It looks like this:
Anyway, recently it's been playing up, the cursor doesn't move smoothly and it seems as if its not communicating properly. Changed the batteries, but still the same. Believe me, having a tempermental mouse while you're trying to do something on your computer is extremely frustrating, especially if its designing graphics. I'm convinced mouse rage exists now - I was not a happy camper the last few days.
The problem it turned out, was that there were tiny strands of dust inside the sensor area (the hole in the circle closeup) that are practically invisible unless you shine a light into it (don't worry, it's not actually a laser in there, it's just infrared light, just like the sensor in your TV remote). Even so, you'd only see it if your eyesight is near perfect.

Those tiny strands of dust seem like nothing, but really affect how the whole laser thing works, giving you sluggish performance and inaccurate movements.
The solution? It's actually quite simple. I just got the dustbuster and held the nozzle at the sensor area for a few seconds, and voila! - the mouse is back to its usual accurate self.
I wonder why Microsoft didn't cover the sensor hole to prevent something like this occurring - maybe they couldn't find a material that wouldn't affect the sensor, and isn't easily scratched as that would obviously affect the sensor.
Hopefully this would help someone out and reduce mouse rage, or wasting more money on a new one (seriously, 200 bucks for the new Logitech MX Revolution? It's a goddamn mouse!).