I POD what everyone else said. Either they are snugglers or they aren't.
I have two cats. Both are shelter kitties. We adopted Princess as a kitten and she doesn't want any part of anyone except my husband. But she still won't snuggle up on his lap.
Blackjack, on the other hand, is our "dog cat". Even though when we adopted him from the shelter he was already an adult male cat, and he was abused by humans and is missing his top teeth because of those monsters, he will come up to anyone - even total strangers, and jump right on their lap and start purring.
It's definitely a personality trait, but I also like to think it might be breed specific as well. I had a Russian Blue that I adopted from a shelter that was the most affectionate cat to me, ever. He would sleep on my head, on my stomach, on my lap. But only with me. Anyone who came near me got hissed at, as did anyone that came near him. But that was probably his personality, too
Good on you for adopting an adult shelter animal - most people want the kittens. Adults have a lot of advantages: they are already litter trained, and they don't get into as much mischief. I agree with the poster who suggested that you spend a lot of time in the shelter with the kitties, if you can.