Rats are usually nocturnal.
But in time, they'll change their schedules over to be with you!
My oldest rat, Da Vinci, was kind the whole time I met him. He came with an aggressive male, who gave me my first real rat bite. So it took me a while to learn to trust him - and him, me. But he was the perfect rat to get me to love rattys again. He's the most cuddly, and tolerant rat I have, if not a bit rough with the other boys.
Rembrandt was the more skittish of the three. I had to force-hold him, and get him used to my smell. Now he's a growing boy; he's the rat that gives me the most kisses.
My latest ratty, Jacopo, was so brave! He was slightly skittish, but never seemed to mind me picking him up. He's a bit of a wuss around Da Vinci, who's 3 times his size, but Remmy and him have gotten along wonderfully. He's the only ratty I have that'll crawl right into my hand.
He's the most playful also - though he's also the youngest.