Just let “good” go. Do not even categorize what you do in terms of good and bad (or not good). Instead, just do the design work. You went to school for it, you honed your skills, you’ve evolved over the course of however many years. Why does it matter if you’re good? Instead, focus on the task at hand: solve the problem, find the opportunity. Be a worker and get the job done in the only way you know how to do it. If you can let go of being “good,” you can focus on delivering what it is you came to deliver.