Why do some people lose enthusiasm after they are hired?

Some people look for a job for the sake of having a job. Those people usually lose motivation as soon as they start working simply because they find not more important goals to pursue.

So many people don't feel worthy as a result of comparing themselves to their friends. Those people usually look for jobs just to feel good about themselves when they compare themselves to their friends.

So many people go for jobs that they aren't truly passionate about. This results in loss of motivation during work.

Some people feel bad as a result of being pressured by their friends to find a job. They usually start searching for a Job because of Peer pressure. (See How peer pressure may influence an individual?)

Some people lose motivation weeks or days after being motivated. Those people are usually the ones who aren't self motivated. Because they get motivated by external factors, they remain motivated for short amounts of time.

Procrastinators usually display a lot of motivation but as soon as they start working they keep delaying things for very long periods of time.

Goals motivate people to keep doing their best. When a person has no future plans he usually finds no reason to work hard.

If a person discovered that his chances of getting promoted are very slim, he might lose hope and stop trying.

People who lack confidence on a professional level might get motivated about a new job then shortly lose motivation because they are too afraid of testing their skills.

Some people move in herds and copy others' goals. As a result those people find themselves in places they don't truly feel connected to and so they lose motivation. (See Why you should not follow the crowd?)

When people form negative beliefs they can easily lose motivation. If, for example, someone believed that he can never get a salary raise then he might not be motivated to work harder.

Some people think that they want certain jobs but as soon as they get them they find that they actually wanted totally different jobs. As a result those people lose motivation.