An employee is a specie engaged in a particular activity for earning a livelihood, but is hardly living (only surviving)
As an employee, he is supposed to be an expert on the subject he is dealing with. With his deep knowledge in the subject, he should able to help other people to find a solution for their problems, but who will understand or even bother about his problems??
An employee earns his daily bread (without the butter) not only from his knowledge, but also through hard work and number of years of experience. No option, but to slog like a donkey and needless to say, donkeys are not idolised.
Professionalism and loyalty must reflect in his words and deeds. Because hardly anything reflects in the bank account
A seasoned employee should try very hard to stick to his commitments and will be honest always. These virtues will help an employee to gain confidence of his clients and employer. Because that is the only thing you gain (refer comment above)
Once an employee gets his reputation, he is established in his line of activity. A dedicated employee works for satisfaction and not merely for money. Because by now he knows that money anyway will not come
An employee learns from his mistakes and utilizes them to bring more perfection to his work or services. Even if he chooses not to, he is reminded by his employer