I think Gempress summed it up nicely for those of us who have fears of certain breeds... It is a fear and it is not rational, but yet, try telling yourself that after you've had so many different, but, all bad experiences with a certain breed.
Talk about statistics. In my case, it's chows, 100% of the pure bred chows I have encountered have been nasty creatures. I have met one, *ONE* chow mix that is a complete sweetheart who will get in my lap at the dog park and give me kisses and it took me nearly a month to be comfortable with this. There are two pure bred chows that come to the dog park sometimes that I avoid at all costs and keep Buddy away from also. Is this fair? Absolutely not, but I'm not willing to sacrifice my dog or myself to see if these chows are going to be the ones that make the skies open with praises of halleluiah comin' down.
While I do not believe that the chow is a bad breed (there are no bad breeds IMO), the handlers of the breed that I have encountered are the ones that have compromised the integrity and beauty of the breed for me and apparently others on this forum. How can anyone fault *us* for this when we've only been on the receiving end of such bad behavior? And this can apply to any who have had a bad experience with any breed...
I'm always cautious around dogs I don't know and I look to the handler of the dog to get a good sense of what the dog will be like. Unfortunately, because of my experiences with chows I have been jaded. It's extremely unfortunate, but for now that's how it is.