There's nothing wrong with self-criticism. After all, you can always improve. But don't confuse self-criticism with self-punishment. Engage in self-criticism that elevates your skills and abilities with a forward-looking approach. Start by reviewing the successful elements of your recent project. Next, divide your assessment into meaningful parameters that you will critique. If your job was to prepare an annual report on widgets for your employer, consider quality, timeliness, use of resources, format appearance, or even self-imposed stress, if you suffer from procrastination, etc. You can divide any project into similar parameters. Rate each one on a scale of 1 to 7 to judge degree of accomplishment. Identify areas for improvement, and review your critique just before your next assignment. Now, attempt to beat your score as you begin working on the new project.