He can be sweet... Sometimes. Ha ha, he's only a year old. When he was younger, all he would do was bite, and bite HARD. We managed to, for the most part, train it out of him. I hope he'll continue to mellow with age!
When ever he bit us, we would put him away for 15 minutes, then take him out and try again. If he would bite and hang on, we would slowly press our finger back further in to his beak until he let go then put him away. I honestly think he'd bite to a) get attention, or b) test us. X) So much personality in a little package, yes?
I have a bird who really likes to hop on my shoulder but she also likes to bite my neck skin and if I try to shoo her away, she'll bite my hand fiercely. FYI: She doesn't like to be held but she don't mind head rub.