'Why MBA' is probably one of the most asked questions when you go for an MBA interview. While it's true that anyone can do an MBA; you can be an engineer or not; it is important to have a clear reason in mind before pursuing it. Once you have this figured it out for yourself, convincing the interview panel to select you for it will become much easier. Post your reason to do an MBA and we will tell you whether it will fly with the interview panel or not!
Meanwhile, you can also watch this video on why people do an MBA and why they shouldn't do an MBA, here.
I, as a PGP participant of the 2016-18 batch of IIM Indore, have certainly been shot at with this question in many interviews, may it be the admission PIs for various IIMs/other top B-Schools or my summer internship interviews or my final placements interviews. The broad guideline to answer this question that has worked wonders for me has been to not focus much on what you are before MBA and what exactly you aspire to become after an MBA but instead, make your expectations from the two years of the course as the epicenter of your answer.
What I mean to say is that talking about facets like the kind of exposure one will get courtesy the high-quality peer group that one gets at an IIM, the lifelong teachings one will get exposed to owing the formidable pedagogy of some great faculties, the learnings from a plethora of extra-curricular activities such as student exchange, sports and cultural fests, rural and Himalayan outbound programmes et al, the practical knowledge gained due to the live case-study competitions and live company-projects, the punctuality and sincerity that will be served right in the form of stringent deadlines and rigorous classes. etc.
All in all, an answer on such lines exhibits to the interviewer that it's the experience of those 2 years that matters the most to you and that you're an avid learner and someone who not just lives in the moment but also fervently looks forward to new challenges, new ideas and new situations.
A blunt answer talking merely about your post-MBA goals as the reason for doing an MBA, in a strong sense, demeans the amazing 2 year-course that an MBA itself is.