The psychology of entrepreneurship ( 2015) indicated the psychological data was collected from participants in four mature economies around the world to provide an international perspective on the human aspects of this balance exercise. It explained the psychological differences of entrepreneurs from the four different countries and the varying psychological drivers behind business creation in each of them. In terms of personality traits, entrepreneurs in the UK tended to be more extraverted than those in the other countries, when German entrepreneurs were the most competitive and the most emotionally stable. German entrepreneurs were not found to be any more conscientious then those in the UK or USA. So, it means different country entrepreneurs will have similar psychology of personality traits to the country's entrepreneurs' characteristics generally as well as it is possible that every country's economic environment ( background) factor won't influence why the country's entrepreneur's individual behavior who have similarity generally. Thus, it concludes every country economy environment ( background) factor can influence the country's entrepreneur's individual behavior choice possibly.How factors influence the differences between small-scale and large scale business performance. Some entrepreneurship psychologists indicate factors can influence the differences between small scale and large scale business performance, due to the differences in behavior of entrepreneur and individual's access to strategic resource and socialization process.Buttner & Makhbul ( 2011) explained factors influence business performance includes among many others: their professional background, their entrepreneurship capabilities and performance preferences, cultural and beliefs, as well as the technology and micro-environment.However, I feel the rate of similarities of large or small scale business failure continues to increase because of the obstacles affecting business performance which include: lack of financial resources, lack of management experience, poor location and marketing promotion, low and regulations banned, general economic conditions, as well as critical factors, such as poor infrastructure, corruption, low demand for products and services and poverty. Other factors include storage of raw materials, handicap in obtaining finance, inadequate competent personnel, inability to control costs and problems of dumping of cheap foreign products and others, e.g. difficult to entry the new (old) market, limited access to other enterprises and lack of employment opportunities from labor market supply or lack of attractive treatment from the entrepreneurship. Thus, what factors influence the performance differences small and large scale enterprises. How to determine greatest obstacles and challenges for the operators of small scale businesses to improve effective small scale business development to expand to large scale enterprises.There is no single criterion for classifying business enterprises as small as medium or large scale globally. However, reference is usually made to some quantity measures such as: number of people employed by the enterprise investment outlay, the annual turnover (sales ) and the asset value of the enterprise or a combination of these measures.Generally, small or medium scale enterprises include the production of light consumer products that are primary related to food and beverages, clothing, electrical parts, automotive parts, manufacture, leather product, soap and detergents, woodworks. Small scale businesses are divided into three sectors: production sector of agricultural processing, manufacturing, and mining . Service sectors and trading sector including wholesales and retails.