How to be committed the job?

Boy, I know what you mean by this and being concerned about getting side-tracked. I like to break each job down into a list of tasks and then keep that list in front of me as I knock out one task after another. I keep telling myself, "I must stick with this and not get side-tracked." When ever anything not related to the job task list comes up, I say "I can not do or pay attention to anything else but sticking to my list." When I complete each small item that gets me closer to my ultimate goal, I encourage myself that I am closer to completing the assignment and tell myself that I will reward myself with the other things that are distracting me when I finish my assignment. Keep focusing on the jobs that need to be done and how good you will feel when they are finished before the deadline time given. I hope this helps and I am looking forward to you posting that you have completed these jobs on time. We are holding you to it!

Yes sometimes the tasks are impossible to finish. When I worked as a clerk for one company I experienced that and I think I am not up into it. Little or no rewards at all, and it is rather sign of bad organization in the company. I guess that may differ from one company to another.
The next jobs that I held are doing only one assignment, and to an extent I am a committed employee. But currently I am depressed over my present job because the people I am working just don't know how to be committed, yeah so irresponsible, if I am from the management and I am committed to excellence, on really bettering services and the world, I would fire them in an instant.
Sorry to rant here just can't help it.
But it's all because of an incompetent leader who can't judge between what's right and wrong, not only in the job, but I presume in real life as well
I can't understand why would he/the teamlead would seek favor of an irresponsible employee. Why want the peer of the "IN" fuc k!ng group. Taking breaks when they should not, avoiding messages/work, lying/fraud, insubordination, eating on the production floor, committing undertime falsifying records equivalent to timesheets; and interrupting other people with noise.
Hugely piss me off.

Depending on the size of the tasks, you may benefit from spending a little time on a gantt chart. You'll be able to visualise and calculate how much time will be required per task and sub-tasks. This will allow you to better prioritise your time by know when an important event will occur and when certain sub-tasks depend on other sub-tasks in order to continue. The other benefit is a nice "flashy" chart that you can show your boss to indicate the progress of the tasks. Should also keep your boss from constantly asking you how much longer it'll take.

You should have a passion for the the work you are doing, if the passion is not there you won't commit, I work at jobs I have a passion for and that makes me do a great job, maybe you should change your field, sorry you feel this way, nothing like doing a job you don't like doing, its torture time goes slow, you don't give it everything you have, I say look for a change. jmo (just my opinion)