Maplin are just the same, lack of real knowledge and always being pushed to sell extended warranties, installations, services and every other bolt on (including 20p screw drivers on the front desk) that they can. I did about 6 months on the shop floor some years ago as a second job and each and every colleague had their own head up their ****, very ego driven and the bum licking they gave to the store manager was embarrassing. I soon left and never looked back.
That's sales for you though, you just blag it half the time; you don't need to know it, but just be good at thinking the customer thinks you know it. I guess it's very similar at PC World. It's all about conversion against that all important footfall and like for like sale targets.