Their absence encourages you to check your phone more often, which means you’ll unlock it and look at some content more often, which means as revenue for someone.

Punching the head isn’t a great idea in general, it’s better to just open palm it and save knuckles for the soft places. Better yet, just use your elbow or forearm, or a baseball bat.

No, either index/middle or middle/ring/pinky.

At the end of the day, you are what you do.