One of the key takeaways, for me:
He was challenging me because he expected more from me. When somebody cares about you, that’s when they challenge you. When they don’t care about you, they ignore you. That’s when you should worry.
It is natural for people to react negatively to critical feedback, especially when that feedback addresses a shortcoming or a weakness in some work, some effort that one has invested heavily in.
It is important to step back and detach the emotional aspect of coming up short of perfection and consider whether this critical feedback is dismissive or whether it is a revelation of some unmet potential that we, ourselves, have not yet recognized.
The whole thing is a good read and great piece of motivation to understand what it takes to succeed.