Some people think that their boss shows favoritism. They're probably right. Small businesses and departments of large businesses are like families: there's the authority figure, i.e., the boss and the children, i.e., the employees. Some bosses might be taken in by flattery, but I strongly suspect that they are in the minority.
Bosses can't help but favor employees who do a good job and who are cooperative. Demanding employees who are always negotiating and who feel that it's their right to criticize the boss are the employees who will not be given the best assignments and who will be asked to leave, first, during a business downturn.