The eyes have it; you know they do. Once you lock onto those baby blues your doomed. Do you really have a choice in the matter or is it the awwww emotion that get's you everytime? You should have a choice and as adorable as that puppy may be she may not be the one for you. As a temperament tester it is my job to see the differences in puppies. And believe me there is a big difference.
A litter of puppies may look all the same; and yes we know they are all adorable but what are you looking for in your puppy? Do you want a dog that just lays by your feet day in and day out? Do you want a dog who acts like it's the fourth of July everytime you walk in the front door? Do you want a dog that will love greeting all your friends and their dogs or do you care? There are alot of things to think about when looking into those big adorable puppy dog eyes.
If you know what type of dog will best suit your family and lifestyle then looking for those specific traits makes raising a puppy much easier. Yes there are behaviors that can change through the simple experiences of life but for some changing is easier than others. And there are litters where puppies are very similar; these are the great litters. The litters where there are differences but pretty much every puppy would fit nicely into someones home without too much difficulty.
Of course there are people who like a challenge; the people who want the tough dogs, the ones who are going to give you a run for your money every step of the way.
It is good that we are as different as dogs and like in humans there is someone for everyone. ;)