[J-dawg]

I'm just beginning to realise that a bit part of mental "toughness" and resilience is actually self-compassion.

Striving directly for toughness can lead to you feeling bad or angry at yourself for having certain feelings, when actually feelings need to be felt, not repressed.

It's shifting your inner monologue from:

"You shouldn't feel so sad about that girl dumping you. You were only together for a few weeks. Stop moping around." to "You're feeling really sad right now, and that's totally expected and ok. It's probably going to last a while longer, and that sucks, but you're going to be fine."

This might be obvious / intuitive for most people, but as someone who always used to default to the first version when "talking" to myself, it's been a big shift.

To actually answer the question, the book that introduced this idea to me was "The Art of Extraordinary Confidence" by Dr. Aziz Gazipura.