No. 1 and 2: “Sir” and “ma’am”
No. 3 and 4: “You’re welcome.”
No. 5 to 7: “Here’s what’s happening.”
No. 8 to 11: “How can I help?”
No. 12 to 15: “I’ll find out.”
No. 16 to 19: “I believe in you.”
Hat tip to: 19 Words That Will Make People Like You More