If someone said something simple like "Your site sucks" I would probably ignore it. However, if someone "disses" my site and gives specific reasons I actually appreciate it. Even if I don't agree with them I like it when someone gives an actual reason why they dont like the site. I look upon that as constructive criticism. Basically I think we all need an objective viewpoint on what we are working on. Often times we are too wrapped up in the job to really notice some of the flaws. In fact I have requested a review here for a new site several different times. I notice that a lot of folks will reply with something like "I liked your site" or "Very nice site". While I appreciate the good comment I wonder if they even visited, maybe they are running up their post counts or just trying to be nice. Either way it doesnt help me to know what changes I should consider. Remember, while you cant please everyone we still need to have our sites pleasant to the majority of visitors (so they will remain longer and return).