Why can't I complete a task I've been assigned?

There are many potential reasons why you cannot complete your assigned task. The first thing that came to mind is that maybe your task is too difficult. Or, maybe it is too easy. Anything moderately challenging tends to be more enjoyable. Perhaps the environment is too distracting - your environment is noisy, or there are visible things in your environment competing for your attention such as your phone or social media. Maybe you dislike that task, and don't see any worth in completing it. You possibly think you should need to do it perfectly, which makes the task appear overwhelming and demotivates you. Maybe you're feeling too depressed, anxious, or stressed to do that specific task. I hope at least one of these reasons apply to you, and if they do, you could research how you could address those reasons.