Small talk and phrases

Business talk is over. Now you have time to get into closer contact to your business partner while dining out.
But what do you wish to say and what do you really say? And what are the Dos and Don'ts? What topics to avoid? What are proper answers to your business partner's story about his cat which was hurt in an accdident in the street where he lives?
Please translate: "Das tut mir aber so leid!" How to answer good wishes to birthdays, anniversaries, Christmas, holidays, weekends?
If you feel like having open questions now- welcome to our training!