Though I do not have a G5, you stated something that I find to be absolutely correct, especially coming from a social sciences standpoint: when people have a negative experience, they seem to be (and this is not true of every individual, or every population of users) more willing to post negative feedback/reviews/comments about that product than people who are having positive experiences using the same product. When you look up product reviews, hotel reviews, or theme park attraction reviews, sure, you get a lot of good reviews or feedback; but there are still those forum sites or Facebook pages where you see a ton of negativity, and I think that that can very often colour one's perception of the product, place, or thing in question.
When the G5 first came out, I was skeptical, to be honest. I looked at photos and looked at MWC postings and yes, I wasn't too keen on it; but now I am warming up to it. I think the G5 is arguably the most interesting phone of 2016 (I saw an article on Google that coined it as such, and I agree with that statement): it's even "infamous" in some forums or conversation circles, I am sure. But it isn't fair that when someone is trying to do real, investigative research on a phone, they are suddenly hit with a ton of negative reviews (or, at least, it seems that way). Of course, opinions and perceptions are subjective; so when you're trying to sit down and see if the phone you're researching checks off the numbered items on your list (which can arguably be objective or subjective, depending on what's on your list), it may be really difficult to iron out what is "reality" (i.e., display: is it as good as that person says, and what does LG say about it? And how do you, yourself experience the display when you test it out in the store?) vs what is something that may be coloured by a negative perception/bias. There's bias in everything...
Sorry, I think I went off on too much of a rant; but I totally agree with you: when you look at the G5 forum page here, for example, you see a lot of people saying they don't like it/returned theirs (and hey, I was in the "I don't like it" camp for a while, so I'm not saying there's anything wrong with people merely stating their opinions!

)/don't like it for X reasons; and it may make things difficult for people who are considering the purchase of the device. But I guess that's why you go to the store and give it a test run!
