It's fun to screw with those guys actually. Because they're just kids off the street who they bring in, fill their heads with all of these terms, then shove them out on the floor to try to convince us consumers which product is best, when they themselves have absolutely no idea what's good and what isn't.
So you walk in there and really confuse them when you ask them about a certain reciever. The sale's guy will say something like, "oh yeah that's one of our top sellers. 7.1 channel, 125 watts per channel. It's really nice". Of course they're only reading what the sticker on the front of it says, so then you hit em up with a question like, "well what's the contrast ratio per channel"?
Either they will recognize the term, not know it has nothing to do with audio and run and ask his manager what the contrast ratio is per channel on that particular reciever (snicker), or he'll look at you like you're a total sucker and say something like, "oh well on this model it's 500,000 : 1, best on the market"! At which point you can retort back, "really, and just how does contrast ratio's work on an audio signal anyhow"? And see what kind of bullshit he tries to come up with. Unless he figures out you're screwing with him.
Next time you think the sales guy is trying to pull a number on you, try this out.