ואמור להם, על מנת שאין לכם אלא פת וקטנית בלבד. רבן שמעון בן גמליאל אומר, לא היה צריך לומר, אלא הכול כמנהג המדינה.

One who hires workers and instructs them to begin work early and to stay late—in a place in which it is not the custom to begin work early and to stay late, the employer may not force them to do so. In a place in which it is the custom to feed the workers, he must do so. In a place in which it is the custom to distribute sweets, he must do so. Everything goes according to the custom of the land [minhag hamakom].

Source: Translation as quoted/translated in Jill Jacobs, There Shall Be No Needy Teacher's Guide. (Woodstock, Vermont: Jewish Lights Publishing, 2010), p. 29. Hebrew text from Mechon Mamre.