Sr.EK :
As for the 'tell us about a time you went against your boss' question. I was successful with my interview and worked for Emirates. I told them a true story that was from when I worked as a secretary for a Real Estate Agent. The former secretary had taught me how to do the job, however i was worried because whenever a sale happened i would draw up a contract but would never do anything in the accounting system to say that the sale had closed. It seemed strange to me that there were just hundreds of 'open contracts' in there. I went to my boss and asked about this, and he said that I had been doing it correctly and that the last girl had taught me everything. I was still worried so I called our accountant, she came straight over and was REALLY stressed. It turns out that the closing process was REALLY important (the agent could have lost his license if we had have been audited) and we worked all weekend to close the sales.
The interviewer asked me how my boss reacted to the fact I had not trusted his word and I told her the truth, that he was just very worried when he realised how big the issue was, and very thankful that I had taken the time to go further.
Basically I think they were impressed that I had taken the initiative to seek someone higher when there was a problem I wasnt happy with. They dont want to hear that you had a 'dispute' with an employer, they want to see that if there is a major issue and your SFS tells you that its not important that you would go to the purser and alert her/him to it... well thats what I think anyway, since my answer got me through =)