They do get kind of cranky when they're molting, especially if it's their first time. They'll be a little bit more moody and unpredictable...sometimes they're friendly like usual, and other times they just want to be left alone and might bite if you bother them too much. I've found though once they've been through molting a couple of times, they seem to mellow out and it doesn't bother them quite as much. Chipper (my budgie) is molting right now too, and she is wanting a little more time to herself right now and sometimes gets a little stubborn and nippy if she doesn't want to come out of her cage. But if I can get her to come out, she still doesn't mind to be petted and will show affection by nibbling on my face, etc. She loves attention, but also wants a little bit more time to herself right now.
Once they're finished molting, it will be like nothing happened and they're back to their old selves.