As a designer myself, I don’t mind getting set deadlines when it comes to client work or projects. If you set a deadline, then you will be determined to work your ass off instead of crapping yourself.

But to effectively benefit from deadlines, you must also have decent self-motivation skills to keep you engaged and motivated on the project you’re working on; otherwise, a majority of people will get demotivated and go off and procrastinate.

Overall, in my opinion, deadlines are the key to success if you stick by it.