People at bike shops generally are there to sell bikes and accessories. That's how they survive. They know how to move a saddle up, down, back and forth - and they can sell you a different stem. Some people who work at bike shops know a thing or two about fit. A very, very small percentage of people who work at a bike shop are actually adept at fitting you to a bike. The shops around here generally refer customers to a professional fitter when the topic comes up.

The reality is that most people go in, buy a bike and ride it without worrying too much about fit. A lot of folks in this thread know their stuff (and they're not trying to sell a bike). So you have choices. Figure out this whole fit thing, get a professional fit or go in and buy a bike and ride it.