I could have guessed. It's not a bad thing to be serious.

[ They balance each other, he finds. Someone serious needs a carefree person to sometimes tell him to slow down and smell the poppies. But a carefree person needs someone serious so that they don't totally check out in life. He has a hard time imagining being so sleepy in nature and serious at the same time, though. ]

I am... But I suppose that's only natural. I like sleeping and not doing too much. I mean, I like making lists and I like my work.

[ Hypnos is no stranger to letting people down. Oops. ]

I doubt someone who takes his duty seriously could let someone down. People tend to recognize effort.