Big 5 extroversion is not that far from socionics extroversion and neuroticism is similar to Ni values.
So basically the positivity is coming from bold Ne and the negativity from valued Ni. But socionic extroversion also includes non-social initiative related to Te.
If you look at the Big Five personality traits—openness, conscientiousness, extroversion, agreeableness, and neuroticism—you’ll see that two of them are especially tied to our everyday emotional life.
Neuroticism, for example, is closely linked to negative emotions. People who score high on neuroticism tend to experience more day-to-day feelings like sadness, anger, anxiety, and irritation. They're more sensitive to negative emotional states, and that sensitivity tends to show up pretty consistently.
But there’s another trait that’s more associated with positive emotion, and that’s extroversion. People high in extroversion are especially sensitive to feeling good. They’re more likely to experience happiness, joy, excitement, enthusiasm—those upbeat emotions. So, extroverted people tend to be more cheerful, more optimistic, and often more resilient when things go wrong.
It’s interesting, because while most people intuitively understand the link between neuroticism and negative emotion, fewer realize that extroversion is actually the strongest predictor of positive emotion.