The paper presents two brief case studies to illustrate the potential problems that exist for 'outside' experts who attempt to change a society's values and reality without, in advance, understanding what already exists, or what the community wants, or is prepared to accept. Both case studies are based in Tanzania. The first examines a situation in which an NGO agent attempted to change the gender relations of a village by introducing new styles of mills for the women to grind millet and sorghum. The second case study is of a foreign-NGO implemented water provision project.