What negative things can be caused by working too long?

First of all why an Employee has to work long hours, Is he incomptent or not enough team members.

For some time it is OK. If it becomes routine then the first impact is on the family life being disturbed. Secondly Employee's on health can be an issue. After some time Emplyee won't e productive.

You would think that working really, really hard is the best guarantee of advancement in your career. If you put in tons of effort, in the end you will get noticed, right?

The reality is quite different though. There’s a reason why employees are expected to work around40 hours a week, and why they get paid vacations (although the number of weeks vary per country).

Here are six reasons why working too hard is bad for you:

1. Damage your health

2. Will lead to stress and depression

3. Working too hard will damage your creativity

4. Working too hard indicates you are not working smart

5. Working too hard indicates that you can’t delegate

6. Working too hard indicates that you can’t prioritize

7. Working too hard indicates you are overwhelmed by your job

Long working is caused by external factors. Stress can also be self-generated, for example, when you worry excessively about something that may or may not happen, or have irrational, pessimistic thoughts about life.

Safety compromise, Low productivity, Stress and Fatigue.

Cost overrun due to waste of time. Most of the employee stay late doing nothing whiy may may lead to other overhead costs.

Long working hours with proper precaution and supervision may require when there is need to finish the accomplish the activity within certain time.

negative influence on productivity, creativity and most important health which directly effect on personal and professional life of employees not only haunt employees as well as their families.

'Stress' is something that finds its source anywhere, not just from Working too long OR under pressure. It's not just stress that resulsts out of working too long...

I have seen some emloyees 'staying back' in office only because they have nothing to do going back home OR they stay away from family. 

I have personally observed the following to be the results of working too long OR working too late with no specific reason.

(1). a member consistently working / staying back late May force management to expect the same from other members !

(2). getting habituated by working long hours - affects personal life & health for sure. 

(3). if personal life is affected, he/she will not be able to concentrate on office work. It will again circle down to professional life - affects quality of work / communication gap with other members. Ultimately, the person will have Zero professional + Personal life !

(4). setting up wrong examples at workplace Or with clients. Gives an impression of immatured time management and not being pro-active. 

Hope this helps. 

Working too long can be mainly because of two reasons. Either he is incapable of completing the assigned jobs in time, which inturns shows his work incapability. However, work load also make people to work for long. This results in less productivity, loss of attention to detail and mental pressure. 

I suggest people to work only8 hours a day and enjoy the rest of the day with friends, family and colleagues . This will refresh you and your your productivity will be much higher.

Working for too long continuous periods can have many negative effects mostly related to our physical & human capacity in relation to stress & exhaustion.

To name some: loss of concentration, diminishing motivation & in extreme cases a burn-out which varies from little to extreme (lasting for months or years).

Working too long can cause stress and exhaustion on the employee.  And because of these, he/she can be less productive.  His/her family life can also be at stake.

The first question to you sir is why you (or anyone else) working too long? 

Lack of planning and/or disorganisation? Well, that what should be covered to avoid too long working hours. 

There are lot of issues, I believe users gave pretty nice comments already, family and private life will be affected badly, and obviously this will raise stress level and cause misbehaving and eventually will affect the project you workng on.

1/ You will be frustrated if the counterparty is not up to the effort made.

2/ Visibility of your planning will be distorted.

3/ You do not go to learn to delegate