My pen finally had the last drops of ink wrung out from it on Monday, and after work I went to get a refill. I went to a normal stationery shop in a mall, and asked the woman at the check-out for a blue 0.5mm F parker refill, she dug for a few seconds in a pile and found it, scanned it, and I paid for it.
Tuesday, I'm writing in my planner and I see it looks radically different than before, and upon closer examination, the refill I was sold was actually 0.7mm M. I go back after work, I ask for 0.5mm F, she digs around again, and takes one out and scans it. I say hold on can I have a look at this, I was here yesterday and you sold me the wrong thing. Upon closer inspection (reading the text on the packaging) this one is 1.0mm M. I tell her this isn't what I asked for. She grabs like a fistful and tosses them on the counter and says very rudely they're all the same. She starts wanting to check out the guy behind me (we're the only two people in the shop) so I say she's being unnecessarily rude and I'll go purchase it elsewhere. She did have a blue 0.5mm F refill, by the way.
Went one floor up to a fancier pen store, guy in front of me was some kind of lawyer getting a fancy pen because his colleagues keep making fun of his small pen/penis [ฤj. pero/pรฉro], he's bantering with the saleswoman, I join the fun. I help him pick a titanium Montblanc. After he's done, I again ask the woman for the refill I want, and she gives it to me. I inspect while she's ringing me up, and I mention the situation downstairs. She offers if I want to test it out to make sure it's good, I say I trust her. I pay the identical sum as downstairs.
I suspect many things are like this. The nicer places are just nicer, and intentionally filter out people by means of aura. Decent overlap of available goods, prices identical down to the last crown, I wouldn't think there's substantive difference in operating cost.