For me it was always very simple: who is delivering the criticism. If it was someone for whom I had respect, both individually and technically, then I listened without taking it personally and discussed the why and the how. If it was someone I didn't respect, forget it. Their opinion didn't matter. Yes, sometimes that led to conflicts. For example, I once worked for a manager that I liked personally but didn't respect his management approach. He was a micromanager in the extreme, inserting himself into every discussion he encountered, looking over your shoulder when working, even insisting that every memo you wrote was reviewed and edited by him first. He'd red line your writing like a high school English teacher. Nonetheless, I followed this approach my entire working career and retired satisfied with the work I had done and with my ego and friendships intact. Nowadays I look back and laugh at some of the many characters encountered on the journey.