Actually in a way what whacks me out the most is people's expectation for an "open" marketplace with high average quality.
If Amazon came alone with insane, draconian policies and made it a very closed market, I'd be ok with that as a consumer so long as I can find what I need.
That sounds like Monoprice or Newegg. Slightly more focused for our needs, but not as fast search results or affordable shipping.
But after getting burned a few times with products that did not live up to the standards presented in bogus reviews or product rankings, now I only use Amazon for the fast shipping. Instead of spending the majority of my time on Amazon doing the research there, I'm spending it on blog posts, reddit, or YouTube looking at real testimonials and going to Amazon only when my shopping is already done. Those extraneous checkout-line addons are no more.
In this way, Amazon definitely does itself a disservice by (seemingly) shifting their priorities away from what they used to excel at to more "big picture" ideas.
I'm only one customer, but clearly I'm not the only one with a growing frustration, and this case (since that's the only one I can attest to) they're losing real money, and I would cause that a disservice.
"minimum quality standard"
Pick one.
Current major issues are:
1. Sellers can name themselves as they like. For example, you can be a seller with a name of very recognized brand deceiving people that you are official source.
2. Sellers either omit information or publish incorrect one. For example, you can sell toys laden with lead and it would be just fine.
3. Amazon has been amazingly unsuccessful leveraging their own data. For example, they can ask simple question "Are you happy with X that you bought last week?" with just Yes/No and use that information to flag products for reviews. Getting rid of incorrect and incomplete listings can not be optional.
4. Listings are not properly conflated which makes people very confused and forces them to spend lots of time to find the "best" one. For example, there are probably dozen listings for exact same product like Syma 107G helies.
It wasn't so bad when the only items sold by third parties were obscure and niche products that Amazon didn't carry. It was actually a good indicator that I might be better off going directly to a site dedicated to bike parts or camera equipment or outdoor equipment or whatever.
But now it seems like every time I search for anything I have to filter out a dozen third party or "sponsored" items that I'm not interested in. If I wanted to be uncertain of what I was getting, have a questionable return policy, and get crappy non-Prime shipping, I wouldn't have went to Amazon in the first place.