1. The search engine is pretty bad. Anecdotal example was when I search for a eye mask: there were two different categories — eyes masks and eyes masks / face pillows. Both gave me the same products, but in different order. Why is that?
2. Sometimes there is no guarantee of quality. When I look for an iPad case or screen protector, it seems that the item either has low ratings or the reviews don’t seem genuine.
Scratch that — third problem is that item description is not uniform or standardized. That makes it hard to compare products; only option is to compare reviews which leads back to problem 2.
And then I get off Amazon and use Reddit to find reviews.
Amazon reviews are a pretty bad indicator of quality. You often need to make educated gueses about whether the reviewer knows what they're talking about, whether their standards are the same as yours, whether they're a shill (which is very common on off-brand items), whether the review actually reflects the product and isn't referring to the shipping or customer servie experience, etc.