Why did you come to a full and complete stop before pulling into a parking lot?

We were all doing 40 MPH on the highway. You slowed down and then stopped in order to turn into a parking lot for Safeway and some other stores in a strip mall. Why? No other moving vehicles were near that entrance of the parking lot. No pedestrians. No animals dodging in front of your car. No scary monsters ripping up through the cement. Did you realize that you almost caused a pileup behind you? Did you hear the sound of squealing brakes behind you, or do you have your senses about you? I can understand slowing down, of course, but STOPPING? Did you hallucinate a brick wall in front of you? Did you feel the need to show the tailgater behind you who’s boss despite the fact that he or she wasn’t tailgating you? Do you need someone to actually tailgate you to show you the difference? I’ve pulled in there before. There are no speed bumps or sudden hills that might make you feel a joltingly terrifying but otherwise harmless up-and-down movement. Black out? Fugue state? Brain abduction?