Shows you're kindly asserting control or authority over a situation, often used by someone in a superior position. I'll thank you to refrain from using your phone during the meeting.
Pro Tip 2/3
Subtle Warning
Serves as a gentle warning that someone's behavior or actions are not appropriate or acceptable. I'll thank you for not discussing my personal matters with others.
Pro Tip 3/3
Cultural Nuance
Might be considered old-fashioned or too formal in some modern, casual contexts, especially among younger speakers. I'll thank you for not speaking out of turn, young man.