Is this your best possible work?
When it comes to your meaningful productivity and creativity, this is the only question that really matters.
If you're not doing your best possible work, ask yourself why. What's holding you back? Is it A) you, or B) something else?
A) If it's you, think about your own best interest, and why it's in your best interest to not do your best work. Most likely, it's not in your best interest to not do your best possible work. Then, it's a matter of shifting focus to overcoming your own resistance to your own best interest. This class of problem is about not being our own worst enemy, fighting Resistance.
B) If it's something else that's holding you back, think about why you're letting something else hold you back. Your best possible work has to take into consideration your environment, your constraints, and what's possible. Get to the limit of what's possible for you, right now. This class of problem is about not being a martyr, but rather being a scrappy cockroach that embraces the constraints and strives to be the most highly adapted creature in your current environment.
I just set up an alarm on my phone to ask me this question every day. It's just too costly for me to not do my best possible work.