I think if you want constructive criticism, you should ask for it specifically when you post your picture. Praise is obviously the default here. One reason is that it's easier to give a positive comment than a negative one. Most artists would accept "that's great" without further explanation, but would require more explanation of a "I don't like that." So I think you're just less likely to see negative comments, because useful negative comments require more effort. Add to that the fact that some/many artists don't want constructive criticism. A viewer is certainly not going to take the time to post constructive criticism, unless the viewer is sure that the artist cares to hear. When newbies join Renderosity and view the galleries for the first time, they will see the mostly positive comments. Through observation, newbies will assume that it is the standard practice to praise to the exclusion of constructive criticism, and will follow suit. And then finally, there must be some contribution from the trend in (at least American) education that has taken a good idea, which is fostering strong self-esteem, and turned it into a bad practice, which is rejection of self-improvement. But I don't think at all that there is anything wrong with the pattern of positive commentary in the galleries. I just think the posting artist just needs to be aware of it and specifically request constructive criticism when that's what the artist wants. The responses to this thread show that there are still a lot of people willing to offer that constructive criticism.