I wasn't asked at all throughout my interview season, but you should know how you want to answer it because it is such low-hanging fruit and there might be someone who runs out of questions and asks, just to buy enough time to find something to talk about.
At this stage you don't need to give them the essay answer, you can just be upfront about how you became interested, what other careers you considered throughout your journey, and why you still find yourself on the path toward medicine and not something else.
I think by the time you reach interview (especially if you have worked longitudinally in medicine), there is an expectation that you can honestly apprehend the good and bad of clinical practice and integrate that into a measured response.
Do not say anything negative, but you can say that despite the imperfect system physicians work within, you really do appreciate the role physicians can play on a team and wax poetic about assuming the honor of responsibility when it comes to a patient's health. Good luck, and congratulations!