Age... It makes all the difference in the world.
What makes a kitten a kitten? Most people think that once the kitten has stopped being a little ball of fluff it is no longer a kitten. This is far from the truth! Cats are considered to be kittens until one year of age. So, they still have a lot of growing and learning to do. And aren't even half way through their kitten year.
Most people will go for the little ball of fluff... They're cute and it is assumed that the younger you get an animal, the better it will bond. That is a myth! It is actually preferable to get an older kitten, which is the reason we don't adopt out our kittens until they've reached at least 12 weeks old. They are still adorable, but most importantly, their personalities are really coming through. Being with their littermates and mother allows time for them to naturally learn how to socialize and be well behaved. They are less fearful, much more trusting, and have learned how to behave politely. (They are house trained, know how to interact with people and other cats, and personality is at an all time high.)
Our Story
We rescued our cat when she was just 5 weeks old. She was meant to be a family cat. However, she was extremely fearful and didn't know how to interact with anybody. She spent most of the time hiding. Being a family cat never panned out. Being that she is distrustful and never learned how to socialize, she only bonded to me. She avoids the rest of the family altogether.
That was in 2000, and now I am still the only one she interacts with. She seeks me out when no one else is around and vanishes when they appear. Relatives jokingly deny her existence. She is a wonderful cat, but nobody but me will ever know it. I blame this on her being taken away from her litter at such a young age. They just aren't ready to cope with the outside world at such a young age.
I firmly believe that unless they are orphaned, kittens should remain with their litters until 8 - 12 weeks old. Unless noted in their profile, all of our kittens are social with each other, my husband, myself, and both our children.