When the bearded dragons beard is black should you not try to handle them?

Ive had mine for over 2 years and if its beard is black that means its agiatied. You can handle it but be carefull in making sudden movements. When mine does this it usually sees another lizard/its reflection or even another charater my daughter has sponge bob stuff everywhere and it then begins the head bobbing . We will rub on its head or under its throat to calm it down , every lizard is differant I know its just a reptile but they all have differant personalities. They will even open there mouths and hiss at you if there pissed off, ours hates going outside in the sun . They will bite and if its a bigger one could draw blood. i wouldnt recommend kids handling them if there puffing out there throats. All and all its a very gentile animal to have just cut the claws tips off once in a while they get sharp.