 The immigrants' thinking, their norms, practices, customs and values shape, extend and influence the native country's culture (Leitkultur).Some such extensions and influences might not be desired by parts of the native population, for reasons that may include practises considered less civilized, restrictions as well as collisions with the native country's norms, laws and values in general.Opponents of immigration often state that immigrants have a net negative effect on public coffers mainly due to the provisioning of medical care and welfare.