Every single question from the interviewer, is a launch platform for you to tell a story. Every single one.
Doesn't have to be a long or a complicated story but every single story should have a factual basis, should be specific, detailed, and should paint you in a positive light. Above all else, it should make the interviewer feel like they've gained some insight into you and what makes you tick.
I.E a bad answer to "why do you want to be a pilot" would be "well I really like flying". No **** Sherlock.
A better answer would be "The first time I really knew I wanted to fly was back in the summer of 1996, when I went to visit Uncle Jim down in Southampton, and he took me for a quick joyride in his microlight. I really enjoyed it and felt that it was something I would like to pursue further, so the following year I signed up for the Air Cadets and started working part time in the local aero club in exchange for discounted flying lessons". You've answered the question, you've expanded on it, you've slipped in a bit of extra detail.
As an interviewer, which answer gives you a better feeling about the guy sitting in front of you?
Every person will have a different answer, make yours factual and honest and relevant to YOU. But just remember, story story story. Every single question, even a simple one like that, is a story trigger.
You can prepare all your stories months in advance. You know you're going to get asked about your early career and history. You know you're going to get a version of "why should we hire you". You should always have a couple of stories ready that demonstrate your CRM and interpersonal skills. You should always have a story ready about performing under pressure. You should be prepared for the "negative" question, about what is the worst thing you've ever done or what are your weaknesses or something like that, and have a story ready to go for that one, obviously it needs to have a happy or positive ending. Have one or two non-aviation related stories ready as well.
The best workbook by far for interview prep, is "Checklist for Success" by Cheryl Cage. Read that and it will help you answer just about every question you could possibly face, without memorizing other guy's answers.