Imagine Person B has woken up in the middle of the night due to a nightmare and is so shocked by it that they have difficulty staying still or going back to bed. 

B decides to text A to distract and calm themselves down. Although A is extremely tired and would rather go back to sleep, A does their best to stay up for B's sake.

 (Bonus: B eventually relaxes and thanks A with an extremely happy text, leaving A to go back to bed with a smile on their face, knowing that B is okay).