Depending on the situation, tipping might be unusual, optional or expected. Almost all bills include a service charge; similarly, some employers calculate wages on the basis that the employee would also receive tips, while others prohibit accepting them. In some cases a tip is only given if the customer is satisfied; in others it is customary to give a certain percentage regardless of the quality of the service; and there are situations when it is hard to tell the difference from a bribe. Widespread tipping based on loosely defined customs and an almost imperceptible transition into bribery is considered a main factor contributing to corruption. A particular example of a gratuity is ("gratitude money") or , which is the very much expected – almost obligatory even though illegal – tipping of state-employed physicians. (Hungary's healthcare system is almost completely state-run and there is an obligatory social insurance system.)