Well done. I was typing my reply while you were posting your answer. When looking aft, ground objects disappear in the veil of reduced visibility, creating the illusion of worsening visibility. When looking ahead, conditions seem to be improving because forward motion causes progressively more terrain to come into view.
When you go through the accident reports you'll find one phrase in a significant percentage of them - "Continued VFR into IFR conditions". The average life span of a VFR or unprepared IFR pilot (and their passengers) when suddenly and unexpectedly placed in actual IFR conditions can be measured in minutes and precious few of them at that. It's very easy to say that "I would never scud run", but when faced with unexpected weather and a need to be somewhere else ("Gethomeitis") you can find yourself rationalizing many things if you're not extremely disciplined. I would dare say that this has been the undoing of thousands of pilots over the years. I personally have known 3 or 4 pilots who were involved in fatal accidents involving scud running and I am positive that each and every one of them had said that same thing to themselves.
A similiar principle affects us professional guys in our turbine-powered aircraft as well. For us, it's the attenuation of our weather radar caused by precipitation. If we allow ourselves to get "boxed in" an area of heavy precipitation, attenuation can cause us to head directly for the worst part of the storm. If we aren't aware of the shadowing effects of heavy percipitation we can be duped into believing what the radar is incorectly showing us - that the quickest way through a line of weather is through the area of a "radar shadow" and this will send you directly into the area of heaviest precipitation. This has caused several airline accidents and cost many lives over the past 30 or 40 years. Oh well, enough of that. I'll get off of my soapbox.
[Edited 2003-10-20 00:33:03]