case studies are simple maths and behaviour is easy. but people there are arrogant and stubborn. one interviewer even made a critical mistake in the case study until I feel something wrong and pointed out, but before it that person look like 'why u are so stupid and don't know such an easy question'. another interviewer for case study tried to make me agree that the strategy you use in manufacturer industry can be comparable to that in credit card industry. job fit interview was funny too, the interviewer believed one of my method in my previous work was not good. well in statistical world there are a lot of families, you can not easily say one is absolutely better than the other, not let alone that method I used is well establised in the industry for a lot of years. finding him/her to be so confident of his/her theory I asked if he/she has a PHD, the answer is no. and that interviewer couldnt understand the method I used in dealing with a tricky problem neither. generally what I feel is that the C1 interview is a paper tiger.big bank usually means laid back work style and slow paced bc they are rich and don't need to work too hard. they are not as excellent or smart as you think . i saw a lot of people here worry about C1 interview. what I can say is to take it easy, be confident, and don't be scared. for more experienced candidates, they can more easily judge the whole process.