This is a huge pet peeve of mine, especially from working in a pawn shop. Yes I know no prices are usually "concrete", but don't just storm in, walk up to something, then shout 'hey how much for this?' when it clearly has a pricetag in plain sight. Typically when people just do this, or ask 'how low can you go?', I will tell them to read the sticker price, and move on with my day. At least make some conversation or offer up a price you'd be willing to pay.

Another issue is sale items. Most things we throw on the clearance table are being sold at or under cost, then people (typically hispanics...) come in and want to give us half of that sale price. Really grinds my gears.