And here's where I'm coming from (cause I've been accused of liking/loving everything I ever commented on..., not in so many words though and certainly not directly).
I listen when I'm in the mood to listen. I also focus on the positive, things that were well done, IMHO. And to this day, theirs no production that was so awful that I wasn't able to find something positive to say about it. And if that were the case, I would simply skip to the next one. I've never felt the need to offer false praise. It's always been spontaneous and genuine. I also usually comment on the mix only and how it translate in my listening environment, which is the same as the one I mix in (that's why I usually specify what I'm listening on). It's an environment I've come to trust with literally thousands of hours of use and some pretty solid hardware. I try very hard not to comment on the creative aspects of a song also, as I believe this is very personal and if theirs one area where it would be easy to offend (not intentionally of course), this is it.
Its happened occasionally that I've found myself at odds with the majority of comments but, this certainly does not give anyone the right to assume that I've been lying through my teeth about it or that I have a hidden agenda as many have here (self promotion and all that sort of thing). A song is a glimpse into the composers soul, and some have literally poured all their emotions into the making of it. You'll never see me knock it down even if I was unable to find anything positive to say about it, after many listens.
Expectations is what it's all about. If I was critiquing a pro, my expectations would be different and my comments would reflect this. But the majority of contributors in the "Songs" forum are not pros. even though the level of expertise and the results could fool you and me at times, I'm pretty sure that most don't have any aspirations beyond making the best with what they have and hopefully get a pat on the back and a well done (and this includes me). I was there to do exactly that, no more no less. But that's my unique vision on how to handle those murky waters, and everyone should be comfortable in doing this the way they see fit. Mutual respect and all that sort of thing.
Bottom line is..., I may not like a particular genre but I can recognize the effort, the musicianship and evaluate the end result fairly accurately (mix-wise) without being an expert. That leaves a lot of wiggle room to find a positive comment and make somebody's day, IYKWIM.