Try driving around and parking in a tight parking garage, then imagine not being able to do it in an S. S has a larger turning circle and is roughly 5" wider. I got overnight test drives of both an S and a 3P and getting the S in and out of my side-load garage was very challenging.
Find a section of road with rough pavement. The route to my Tesla store included several miles of concrete pavement that the 3P suspension just couldn't deal with. Standard 3 AWD was significantly better. I was really surprised at the difference. S of course better still.
Do you haul bikes, skis, or anything else that might be an issue in the 3's trunk? S is cavernous and the hatch makes it that much better.
Not as exciting as suggesting ways to experience the nimble handling of the 3, but sometimes practical things matter too. Both are obviously amazing cars. Overnight test drives are a much different experience compared to a 20 minute drive around the local store. I had about an hour from home to the store and it was really good to be able to experience seating comfort and a wide variety of roads and speeds.
Big shout-out to the Littleton, Colorado Tesla store. Great people, very patient with a someone like me struggling with a decision on an expensive purchase. I'm really hoping Tesla and Elon are starting to understand the value and importance of the people who directly interact with customers. Whether now with a 3 or in a couple years if I decide to wait for a Y, I'll be a Tesla owner, and it's because I was able to have such a great personal interaction with the people.