I'm an introvert.

source : #10 내성적인 성격이에요

Michael was crossing the Han (river) by subway.

외향적인 사람 / 내향적인 사람, 내성적인 사람

He's an extrovert.
I consider myself(to be) an extrovert.

He's very outgoing. (or sociable)

He's extroverted. (외향적) / He's introverted. (내향적)
He's an introvert.

Despite his profession, as a Youtube broadcaster, he considers himself an introvert.

The train was pulling into the station, so Michael had to go.

I also think I'm very introverted.