DH and I recently bought a new (to us!) second-hand car. This is fairly significant because since moving to our current city 4 years ago we've lived car-free, using bicycles and public transport. It's been fun, but we made the lifestyle choice that we want to have a vehicle again. The car we got is fantastic - very small and compact for city use, fairly economical to run, but also has a powerful engine so suits DH's mechanically minded sensibilities.
DH took the new car around to show my brother and sister-in-law. My SIL simply could not get her head around why we'd bought such a small car. "That trunk is so tiny, how will you fit your groceries in it?" was just one of the many concerns she kept expressing.
She didn't seem to understand that we've managed just fine for 4 years with no car, and that ANY car is going to significantly improve the convenience of shopping etc! Nothing DH said could convince her that the car is exactly what we want and will make our lives much better! (Incidentally, the grocery store is less than 5 minutes WALK from our house. We either walk down or if we need a big shop then we order online and get free delivery. Really the car makes little difference to that!) Sure, if we want to buy a giant piece of furniture or similar then we'd probably have trouble transporting it, but that applies to most cars! We've since been around in circles a few times with SIL, but she still doesn't seem to get it. Our lifestyles are just very different, clearly! We are having a baby in the new year which is potentially impacting on her perspective, but again, having a car can only make things easier for that, we don't need to go from no car to a giant people mover just because of a new baby!!! We have no need or desire to own one of those gigantic tank-sized strollers anyway, so the fact I can't fit one in the car won't be an issue... there really is more than enough room for the baby and any other paraphenalia - it's not as if we got a 2 seater sports car!