Obsequiousness is nothing but a form of opportunism. An obsequious person exhibits behaviour designed to win the sympathy and support of others. What characterises obsequiousness, or flattery, in a negative way, is the lack of sincerity and spontaneity inherent in obsequious behaviour. Actions, even those that appear to come from a genuine sympathy for the person concerned, are in fact motivated by personal gain. An obsequious person is disingenuous by definition. The adulation that he/she often shows people is supported solely by self-interest. Once you he/she has what they want, an obsequious person can indeed change his/her attitude towards the person until recently flattered; once the objective has been reached, it is no longer necessary for him/her to fake politeness and friendliness, and the obsequious person can then behave according to his/her true nature. Opportunism, which is what obsequious behaviour is based on, often leads to a U-turn as soon as the objective that motivated this behaviour has been attained.