When we set unrealistic expectations for ourselves and others, there are a number of consequences that follow. On one end, the person who created the expectation will feel disappointed and frustrated when the other party fails to complete what was expected. When a person feels like they're failing something, it's extremely easy to attack our self-confidence and self-esteem. When our self-confidence takes a hit, it becomes exceedingly more difficult to complete tasks and live up to the expectations set for us. They may not have been unrealistic at the time, but circumstances constantly change, and what was realistic at one moment may not be the following day.