I believe in the saying that experience is the best teacher. Most of my self improvement and development in my youth came after some teasing and mistakes. I didn't change just because of the teasing, but those helped point out what was wrong with what I am doing. So I learned to look after myself, improved my hygiene, how I present myself, and other things. Since then, I have been my own worst critic. I constantly strive for efficiency, and I take what I think are good things from others to help improve myself. This has translated to work ethic, performance, and presentations.
Mistakes and failures are an amazing way to learn, develop and grow.
I don't think there's anything wrong with seeking to be more efficient, continual improvement is a far better thing to seek that perfection; the latter is unattainable and the former within everyone's grasp.