We have two cats and they have very different personalities. Our tortoise shell calico was raised in this house and we were affectionate to her when she was little. I was a stay at home Mom and my kids and I were around all the time. (LOL...maybe she had TOO much love??) She is pretty stand-offish and doesn't like to be picked up. She'll be affectionate toward some people (no real rhyme or reason there, although I think she can sense who she's safe with) and will rub against you lovingly. But even with me, as her favorite human, she does NOT like to be picked up. She used to sit on my lap a bit, and used to sleep with me, but that changed when cat #2 arrived 1 1/2 years ago. That upset the apple cart a bit (a lot) and although we have achieved a degree of peace there are still days, every now and then, when cat #1 will give me attitude and swat at me for no apparent reason (I think, again, that she can sense when I'M having a bad day and she doesn't like it, puts HER off her comfort level)
So...cat #2 is the most affectionate cat I've ever known. She will jump into your lap two seconds after you sit down and take you over. She licks, snuggles, etc. She does this with people in our family, who she sees regularly, but she'll also do it with anyone who walks through the door. She sleeps on our bed at night....either on my husband or me, or on my pillow, wrapped around my head. She just seems to have been born to be a lover.
Now, what I can say is that the former cat was raised in my household and she was the first indoor cat/kitten I ever had. We'd had some outdoor cats before that but they had all fallen prey to our busy road. So, when we got this little girl I told my family she'd have to be indoor-only. We had always been "dog" people, for the most part. I know I was skittish about having a cat in the house, since I didn't know a lot about them. The latter cat was raised in a household where cats were as much the norm as dogs, and her human family was completely comfortable with cats, and with having them inside the house. (they raised something like 21 over the course of 40 years). So, I DO think that, in some ways, it is possible that the cat's differing personalities are a result of their environment/upbringing. While we didn't NOT give "my" girl love and affection, we certainly weren't as comfortable with her as my new hubby was with "his" girl when she was a kitten.
Thanks, glitteringfuzz, because this is the first time I've really thought about MY discomfort with her as a kitten being a part of the reason for her personality development. And it makes so much sense; I can't understand why I never thought of it before.