We should keep in mind that utility is not a property of the goods themselves. Utility is in the mind of the consumer, and consumers change their minds. Their tastes change; their circumstances change; their consumption patterns change The utility that people get from consuming a good wil depend on the amount of other goods they consume.A change in the amount of other goods consumed, whether the substitutes or complements, will shift the total and marginal utility curveWe should keep in mind that utility is not a property of the goods themselves. Utility is in the mind of the consumer, and consumers change their minds. Their tastes change; their circumstances change; their consumption patterns change. The utility that people get from consuming a good will depend on the amount of other goods they consume. A change in the amount of other goods consumed, whether the substitutes or complements, will shift the total and marginal utility curve