My parents turtle (Nostrils) is extremely friendly. He would be an awesome therapy animal, if it weren't for the salmonella. Has not bitten or hissed and is around 25 year old.
Any chance he see people....especially children he goes bananas. He's very inquisitive about peoples faces, and will get right up to your face, and smell your hair if your comfortable having him so close.
He can spend hours sitting on people, whether its your arm, hands, your leg, feet, or your chest. He's big on smelling your skin or your clothing - not sure why.
He will follow you from room to room and enjoys being part of the action, especially when the grand kids are near by. He will follow them around the house almost to the point that the kids need to make sure the turtle does not see them going downstairs, because if he could talk he would say - "hey wait for me."