They have so much love to give
Despite what some people may claim, cat owners know that felines of all ages can be extremely affectionate. Senior cats, however, usually aren't as hyper or easily-bored as they were in their youth, and a nap in your lap might just become their favorite afternoon activity.
Additionally, if they were raised in a family environment before being adopted by you, they've already learned how to behave around people and to trust in their human companion. That means they can often be less skittish and unpredictable and more eager to love.