When should we say yes and when should we say no?

I really enjoyed talking with you this morning. As you told me, by saying just \"how are you\" we can\'t stop talking. ^^ Furthermore, I would like to say my story how to eat leftover in my way in next class. Your day is almost coming, so enjoy yourself. Han. When should we say yes and when should we say no? It is hard to define the situations. I do my best to say yes because of my job. While I am handling the guests in the hotel, I always try to say yes. But if the requests were based on the money, I would try to say about additional charges to the guests politely instead of saying No. If someone asked me to smoke, I would say no at that time.^^ Because I don\'t like to smoke, and pay the tax for my country. Even though some tasks is impossible for me, I usually try to do it first.