From Wikipedia:

Behind the smiles and charm, rats can be terribly obstinate and controlling, insisting on having things their way no matter what the cost. These people tend to have an immense control of their emotions, which they may use as a tool to manipulate and exploit another person, both emotionally and mentally. Rats are masters of mind games and can be very dangerous, calculating and downright cruel if the need arises. Quick-tempered and aggressive, they will not think twice about exacting revenge on those that hurt them in any way. Rats need to learn to relax sometimes, as they can be quite obsessed with detail, intolerant and strict, demanding order, obedience, and perfection.