No-one's life is smooth and dandy. You must have had some difficulty, some challenge. Maybe a loss of a family member, maybe you failed an exam, maybe you had to climb a tall mountain on an exped, maybe you really wanted the part of Tony in West Side Story but didn't get it. It isn't the episode itself that the board will be interested in, but what you did about it that matters. It doesn't matter what anyone else did, it is what YOU went through and what YOU did about it that counts.
Ollie, like many job interviews, the interview part of AIB is competency based, you will be asked when did you do ............., etc. The best way to approach these things is thus:
Sit down with a pen and paper(lots of) list all the things you have achieved, even small things like passing exams etc but things from which you gained a sense of achievement or satisfaction are better. Turn each of those into a short 1 paragraph story with a beginning introducing the achievement or challenge, a middle which explains what you had to do and most importantly an end which explains the result(what you did to overcome the challenge etc). Think back, achievements like helping a friend in a time of need demonstrate teamwork, coaching skills etc, things which may seem irrelevant are often not..... DO NOT LIE especially to yourself!
Apply the same approach to how you heard about the RN, what appeals about the RN your branch preference etc. All these little stories will stick in your head because they are your experiences, they also serve to help you communicate your thoughts in a logical and intelligible way. Now all you need do when questoned is present an appropriate story to the board, you won't have to sit there like the "thinker"