There are many college students who are bad at keeping themselves in line． When they are required to finish some assignments， they will barely bother to do it unless they deem that they may be criticized by their teachers． Instead， they spend their time playing computer games and watching episodes of TV programs， as well as chatting with friends on MSN or QQ． They oftentimes procrastinate so terribly that they have done nothing before they go to bed． Despite the fact that every day they tell themselves that it will be a fresh start， they just succeed in repeating their procrastination． Undoubtedly， these students have not realized the importance of self－discipline in their lives．
　　Firstly， the world is full of temptations to live an undisciplined life． In today’s society， they live in a world where temptations are almost everywhere． There are a variety of TV programs that tempt them into knowing what have become of the hero and heroine in the last episode． There are various occasions on which they find it hard to decline their friends’ invitation． Though they make efforts to focus on professors’ assignments， they usually surrender themselves to the mercy of entertainment activities and tell themselves to put the homework later on only to find out that the homework is not finished at last． In consequence， they have no respect for themselves． In fact， they hate themselves for being like this． But whatever they aim for a change， they just fall back into their old ways． This is what their lives will be like if they do not possess self－discipline．
　　Secondly， as various interviews given by most of the successful people in the world show， self－discipline is one of the qualities that help people succeed in their chosen fields． People who have the ability to reject instant gratification in favor of something better， to follow actions by overcoming addictions， procrastination and laziness， to resist temptations and distractions， are more likely to attain aims and goals． On the contrary， lack of self－discipline leads to failure to reach goals， even minor ones， and to loss， health， obesity and other troubles．
　　In sum， self－discipline is one of the essential qualities that contribute effectively to a man’s progress and development． While the world is teeming with temptations and distractions， one can only succeed by learning self－discipline．