Chris Pruett writes on the Robot Invader blog:

Good player handling code is often smoke and mirrors; the player presses buttons and sees a reasonable result, but in between those two operations a whole lot of code is working to ensure that the result is the best of many potential results.  For example, my friend Greggman discovered that Mario 3's jumping rules change depending on whether or not a level has slopes in it. Halo's targeting reticle famously slows as it passes over an enemy to make it easier to target with an analog stick without using an auto-aim system. When Spider-Man swings, he certainly does not orient about the spot where his web connects to a building (at least, he didn't in the swinging system I wrote).

Good player handling code doesn't just translate the player's inputs into action, it tries to discern the player's intent. Once the intended action has been identified, if the rules of the game allow it, good player handling code makes the action happen–even if it means breaking the rules of the simulation a little. The goal of good handling code isn't to maintain a "correct" simulation, it's to provide a fun game. It sucks to miss a jump by three centimeters. It sucks to take the full force of a hit from a blow that visually missed. It sucks to swing into a brick wall at 80 miles per hour instead of continuing down the street. To the extent that the code can understand the player's intent, it should act on that intent rather than on the raw input. Do what I mean, not what I say.

I suppose this explains why I am better at arcade bowling games than I am at actual bowling. More seriously, while I had some vague awareness of this, I am slightly surprised at the breadth (Mario 3!?) and depth to which this "control re-interpretation" takes place.