You learn something new every day!

So, we called the plumber back about our sink issue yesterday.  It turns out that sometimes when a plumber does really intense work, such as replacing a bunch of pipes, the disruption can cause rust and deposits to drop into the lines, and when you turn on the water, all of that stuff gets flushed to the end of the faucet, blocking the water flow.  Sure enough, Matt removes the end of the faucet, and there's a bunch of crusty crap in the filter.  This is a good thing to know, considering the calls I get at work!