I took a ride in one of my 1950s cars yesterday and decided I've got some work ahead. The car ran very well, the lights all worked, the tranny was shifting fine and the brakes stopped the car.
But the front end was all loose and wandering, the left-hand turn signal indicator lamp worked off and on and there was a rattle from under the dash that would just drive me crazy on a long ride. Under hard application of the brakes, the car also pulled to the right. And the power steering hummed.
Going and stopping are important, but is you want to do safe and comfortable driving, the little problems need fixing, too.