My male Green Cheek gets into these moods, they are "sassy" little birds that occasionally get the idea in their heads that they rule the roost! I think with Bowie (who is now almost 2 years old) it's partly hormonal, or at least it started out from the start of his puberty, and then he decided that he liked his new "badass" persona, lol...What he doesn't like, however, are "time-outs", lol...
I love these little guys so much, in my opinion they have more personality, charisma, and yes, attitude, than the huge birds do. That being said, you have to keep them in-check, otherwise they will take-over!
Time-outs work extremely well with Bowie, hell, just me totally ignoring him for 5 minutes and not answering his calls to me drives him nuts! If he starts to get nippy with me I just put him on the floor and start doing something different, with my back to him...That's when the calls start, he'll eventually start yelling "BABY! MY BABY!", and "GIMME KISSES!" followed by his kissing noise, and when I don't answer him at all he loses it. After about 10 minutes he's totally quiet and mopey, he usually retreats to his cage in defeat with his head hung low, and at that point I go get him, and he's on his best behavior again.