The word "NO" doesn't mean the same thing in all countries!!
I learned this and I will try to explain this by using 2 examples:
example 1 :
A while ago, I met a russian girl (an erasmus-student)
One evening she invited me for a cup of of tea....In Belgium, we would never do this, it's just a habit that young people normally don't do. For us, this is something for old people?! (=Cultural difference)
But I just couldn't say "NO" to her because she insisted ... So I agreed ...
Then she also insisted that I ate a cookie. She REALLY INSISTED. It even made me feel that it would be very rude to say "NO". It made me feel as if I would have said "NO" to her, she would think that I didn't like her. So, I ate one, but wasn't hungry AT ALL, but she was happy
example 2 :
Almost the same thing happened to me with a Turkish girl. She asked me to come to a party....
BUT I had a test the next day so I had to study
In this example I did say "NO" because of the test. And, as I expected a little bit, she didn't really understand that.
A Belgian girl would understand this giving the circumstances but it seems that, if a girl asks you something in Turkey, all men normally say "YES". The girls see it as an insult if you say "NO" to them, the reason why is less important.
Conclusion :
Think twice before saying "YES" or "NO". And always watch out that the other person interprets this "YES" or "NO" the way that YOU mean it!
, but she was happy 
so I had to study 
