One of the most common and oldest rituals in Buddhism is given food to monks whilst they do their alms rounds. It shows us not to be greedy or selfish.
Buddhist monks did not build temples or monasteries, they instead were known to beg for their food, the only possessions they would own were a begging bowl and their bowl.
Monks normally do not speak to anyone or say thanks, the alms giving is not thought as of charity to to make a connection, laypeople have a responsibility to support their local community spiritually.