There is a M2 at the rescue who has the rep of being unpredictable b/c he will be cuddling one second, and bite you the next. But I've learned to read his body language. When he actually wants you to pet him, he holds onto his perch with his beak and won't look at you at all. When he's getting excited and about to bite, he'll take his beak off the perch (still resting it on the perch but turning his head toward you) and stare at you for a few seconds before he lunges.