He that is good for making excuses is seldom good for anything else (Benjamin Franklin) 

Most of us are guilty of having done something we shouldn't have or of not doing something we should have. When we are questioned about our misconduct, do we accept responsibility and admit we are at fault? Usually not. Instead we make excuses.

Excuses are harmful because they prevent one from succeeding. When we make excuses and repeat them often enough, they become a belief. The belief then becomes a self-fulfilling prophecy. For example, a sales rep discouraged by his poor sales starts to blame the price of his product. "No one wants to buy it because it's too expensive." he says. After repeatedly making this excuse, he begins to believe it is true. 

Making excuses can put the brakes on our progress, while accepting responsibility can lead us to the top.

How to stop making excuses

1.  Realize that your success or failure depends on you.
2.  Beware of rationalization. 
3.  From time to time, stop and examine your progress. 
4.  When you make a mistake, accept responsibility

Siit.