Thanks for commenting! Yes, deep gratitude goes deep down to clarify how exactly other's contributions affect you positively. That is that you go beyond a thank you, saying how the fast or effective reply to a request saves you time to leave the office on time or get done with other stuff. It means that the person is affecting your well-being because having gratitude feelings is indeed a plus. You can also let them know that. That their contribution has made you experience this feeling. Surface gratitude, on the other hand, looks mechanical and nonpersonal. It may not even have any effect on people. When you say thank you without even making eye contact or mentioning the person's name.