1. "Most of it was done by you this time, so how can I possibly accept such generosity?"
2. "Without you all handling the trivial matters, it wouldn't have been so smooth."
5. "Of course, I insist on treating you!"
6. "You really are.."
7. "...I remember, when you just started, you used to come and seek advice from me."
8. It's just that your expression looks a bit scary, haha.
9. "Excuse me, where should I submit this document?"