It's Writer's Friday. So Write right, today!
I struggle with this. Honestly I think most writers do, to some degree. What I understand is that universal emotions shouldn’t be told. We should show how the character reacts to their feelings. We all feel nervous, sad, happy, or angry. These are universal emotions, everyone has them. But we all react differently to those emotions.
If a writer just tells you a character is angry, that’s boring and uninteresting. We’re reading the story. We see what caused him to be angry. Someone ran into his brand new sports car. I’d be angry too! More interesting is how he reacts to seeing his dream car smashed. Does he jump out of the car yelling and cursing? Does he calmly and methodically take out a gun and shoot the offender? Or does he just sit there and cry?
Even in a first person narrative the character knows he’s angry. It’s more interesting for him to show what he is feeling or what he’s thinking, instead of saying “I was angry!”
Showing applies to descriptions and relationships too. It’s boring to hear that someone was ugly. What makes them ugly? Show it! It’s boring to hear that two people are close. How are they close? What do they do together? Show it!