I tend to ignore good reviews and rely on bad ones mostly to make my decisions. Will also never leave a good review when I'm satisfied, they are indistinguishable from fake ones anyway, I tend to rather just leave bad reviews when I'm not satisfied.
Also, if a product is popular enough, odds are that even with a great product there'll be a small fraction of people who'll just happen to get a dud, while most of the rest will be satisfied.
Because of this, I tend to read both good and bad reviews, and give more weight to the longer reviews that go in to great detail about the product and why they rated it the way they did, with comparisons to other products being especially helpful. Also helpful are reviews by professionals who really know the field thoroughly. Unfortunately, such reviews are rare.
I also look at the ratio of good reviews to bad reviews, and look for products with many reviews, though on Amazon this strategy is not quite as effective these days as it once was. One of the big problems with Amazon's model is that it seems that most people buy the products shown on the first page or two of search results. Products on later pages might be just as good or even better, but they may never get bought or reviewed because they weren't on the first couple of pages.
I have also noticed the tit-for-tat reviews on Amazon between competitors. Its quite common on the cheaper products, in my experience. I've bought one or two awful things due to being caught by fake reviews, but I do tend to go back and leave a dreadful review.
Blows my mind how amazon is not paying more attention to this issue, i used to get almost everything on amazon - not so much anymore.
Add that Amazon are determined to show thirty no-name brands of cheap (and nasty) copies of whatever item you searched for, sometimes making the actual market leader really difficult to find, and it becomes more trouble than it's worth. I don't have hours to micro-manage and investigate every £10 purchase for fake product, fake review or not the brand I really wanted.
As a hugely keen early adopter of online shopping, these days I just go to the shops more and more often. It's just a shame there's so many fewer of them!
This is basic consumer behavior. Receiving a good experience (either service or product) is not notable because you paid for it and expect it, whereas a bad experience is offensive and makes you feel cheated so you retaliate by taking your time to leave a bad review.
What this means at scale is that most positive reviews are fake except for the truly extraordinary products/services that are far above all their peers in terms of quality or novelty.
In order to get decent reviews you have to be able to verify that the consumer actually paid for the product/experience and then you have to apply some sort of sampling methodology and statistical analysis to arrive at a meaningful relative score to other products/services in the same industry.
No review site has any interest in doing this because they are just using reviews to generate free content for SEO, to put ads on, and to extort businesses into paying them to "manage" negative reviews in various ways.
A review can have a certain quality and/or amount of details, that makes it obvious that the reviewer actually owned and used the item. If I think it's worth sharing the quality (or lack of) of an item, I put effort into producing a review that it's clearly real. Reviewers also have a history.
So I think it's not correct to state that the good reviews are always undistinguishable from the fake ones. Of course, with enough effort, a fake review can be made real.
When a product has way too many good reviews I usually try to see if similar products show the same reviews. It's outrageous how much copy paste is used.