As far as kittens go, I think it's all in how they are raised. We have had several sweet, friendly kittens leave our clinic and come back nasty and aloof. Even the owners complain about the cat's temperment. Often the problem began when the owners started to play to rough with the kitten and he grows up to think that it's ok to bite and scratch. If you teach your kitten that rough play is not acceptable chances are you are going to have a better tempered cat.
Also with kittens they need to get used to have things done to them like brushing and claw trimming so when they are young is the best time to do it.
As for trying to find a lovable kitten, you can pick out the most affectionate in the litter but often they will grow up to be anything but a lap cat. If you have an idea of the kind of cat you want, trying to find him as a kitten can be very difficult because you never know what you're going to get. You can try and raise him to be what you want but they have their own personalities and your efforts usually just wind up shaping that.
I adopted my cat, Xavier, as a kitten and thought he was going to be a real snuggler. He's almost three now and HATES to be held dispite all the holding he got as a kitten but he is real lovable... On his terms. Just don't expect him to curl up in your lap. LOL
That's why for me adopting adults is a better option. You get a better glimpse of their personality and you're saving a cat that could otherwise end up being euthanized because there wasn't anymore room for him.
I have three females and two male cats and I don't see much of a difference in them. They each have a very unique personality and they are all very active and playful. It helps to ensure they don't become overweight because that will suck any energy out of a cat. I also make sure I take a little time each day and play with them all with different toys. A bored cat is a sleeping cat so keeping them stimulated keeps them active and playful.
When I adopted my cats I saw big changes in their personality vs. the cage they used to be stuck in. I never expected my cat, Peaches, to be so affectionate but she is. She enjoyed be petted in her cage but once I took her home she started to follow me and my boyfriend around, begging for attention.
Fallon, was mellow and low key but liked the attention while she was waiting for a home and when I took her home, it took her a couple weeks but after that she constantly needed to be around me. If she wasn't she'd cry and cry till I came and let her know where I was. Her spunky side also came out which I was kind of shocked to see. She'd walk on her hind legs over to the dogs, waving her front feet in the air, smack their muzzles and take off into the other room.... Only to come out a few minutes later to do it again.
Sampson was very misleading because in his cage he was very affectionate and loved to cuddle. When I got him home he became very independant and hated to be held. I still love him to pieces even though he wasn't the cuddler I thought he was going to be.
So no matter what you get you'll get attached and love their personality no matter how they turn out. It's difficult to choose one out of so many but I've found that when I met each of the cats I have now, I just knew deep down that they were comming home with me, no matter how I tried to talk myself out of it.