My sleep.

I used to use smart phone before I lie on bed before bedtime. I know that I shouldn't use them. But the dopamine generated by digital devices and internet is too cheap. When I am unhappy or under pressure, I tend to use my smart phone. And I am always unhappy or under pressure recently. Then I use smart phone before sleep. Then I fall asleep very late. This creates some vicious circle. The worse my sleep is, the more unhappy I am.

I can no more live with a digital device in the same room before bedtime.

Before I go to bed, I have to leave all my digital devices, except for kindle, at first floor. Then I return to my bedroom at second floor. Without them, I can finnaly sleep well.