Lahei means that you don't want to receive messages from this person, but you can still see each other's movements.

After you delete a friend, you will no longer receive messages from that person, and the friend will not be able to add you as a friend again. After deleting a friend, you will still be in each other's friend list and can also receive each other's messages. When you receive a message, the other party will be in your stranger.

And in the description of life figuratively and so on, pulling the black can be applied to the once familiar people or things forever cut off the emotional resistance behavior. It is now a more fashionable and subtle expression of the adjective.

Extended information:

Theatrical usage

When you don't want to see someone's comments in an online game, you can right-click on the other person's nickname in the chat box and choose to block or add to the blacklist, or you can manually turn on the human relations /Friends/Blacklist/Add Blacklist. From then on what the other person says will not appear in your chat box.