A sense of control
Ha ha haaaa! I knew my human wanted to go to her 'puter room and do email and LJ stuff, but I'm not allowed in there (she says something petty about my propensity to chew and sever cords). So I made her stay with me instead by curling up in her lap and purring -- I know she can't resist that. Ha, now she'll barely have time to log in and she'll have to go to sleep. Nyahh! I have her wrapped around my little pinky-claw!