Summarize this article in one sentence.
Only provide feedback if you are truly trying to help your coworker and improve your work product. If you are criticizing because you do not like the person, are frustrated, or are stressed, keep your criticisms to yourself.  If you are not criticizing someone for the right reasons, try talking to a friend or family member so you can vent. Feedback should only be given for a specific purpose not just for the sake of doing it. Once you identify a specific issue, think about the changes that need to be made and what can be done to achieve them. You are much more likely to see changes if you have a proposed outcome. The criticism you give should be a learning experience for your coworker. If the issue was a late report, you may think of ways to increase efficiency such as setting small milestones and breaking down the project into multiple reports. This is much more helpful than saying your report was late, you need to work faster. You don't want to confront a work colleague in front of others, so pick somewhere private. Additionally, you don't want to criticize him if he is having a bad day already. He may be in defensive mode, in which case he will not be open to any form of suggestion, especially a criticism. If the person is about to finish a project or is preparing for a presentation, wait until they are finished before you criticize their work. Your feedback is not helpful at this time and will not change the outcome of the work.

Summary:
Examine your motivation. Decide what outcome you would like to see. Choose the right time and the right place when approaching a colleague with criticisms.