It's entertainment to me.
My wife used to do mystery-shopper work in Currys, Dixons, etc. and drag me along. Basically all she had to do was buy things, act the idiot, check prices were correct, etc. Sometimes she did a longer "audit" where she had to check hundreds of items were priced correctly and drag the manager around with her.
I took to entertaining myself while I waited by listening out for the "advice" handed out and correcting it where people were not just stupid but obviously trying to scam punters. But it's not just Dixons, Currys, etc. - good staff are hard to find everywhere. I was in Maplin's only the other week and was watching a poor couple being "talked at" by one of the sales staff. They were buying a portable hard drive (I don't even know if that's what they wanted, but I assume it was) and the sales guy wouldn't leave them be. Instead he was *insisting* that they absolutely NEEDED a surge protection strip to plug it into. As in, the thing would blow up and die if they didn't because it was so fragile.
The poor couple had no idea about computers whatsoever and were literally umming-and-arring over getting the surge protection strip. Sales guy wandered off to find one and came back with a £50 model (!) that he insisted they must have (the same price as the damn drive they were buying!). He was so insistent that they honestly thought it was something vital (even to the point of "Oh, yes, I've seen one of those at X's house and he has a drive too"). The sales guy got distracted and went off (presumably to find a more expensive model).
At this point, I considered it my geeky duty to step into the conversation and whispered in the couple's ears that I'd worked in IT for 15 years, couldn't imagine a situation where a surge strip would actually be needed in London, certainly not one that would save you from corrupt data (or where the stuff on the drive at the time of this "supposed" lightning strike would figure against the cost of rebuilding your home after the fire), and had yet to ever hit a situation that required a surge strip for anything - certainly not just a portable hard drive. And if they REALLY wanted one, Argos sold one for under a tenner. They thanked me, and bought the drive and left while the sales guy's back was turned.
(I would have pointed out that for £50 they had a UPS on the shelf behind them instead of a silly extension-lead-with-a-fuse and that would do an infinitely better job at surge-protection and their drive not conking out mid-power-cut, but didn't want to confuse matters.)
And then people wonder why I get stroppy about the constant "Can I help you, sir?" and "advice" offered by these people and never buy anything from those stores (a poor relative bought me a £5 Dixon voucher once - I threw it away after finding there was NOTHING in the store for less than £10, not even a USB cable, or something simple). Your sales staff are there to help. If they can't help, they are useless. Most sales staff actually ARE useless in any technology-related place and I tell them where to go as politely as possible.
"Can I help you, sir?" Yeah, stop insulting my intelligence with your prices, your undertrained staff and your sub-standard products. Thanks.