I've visited the Kettlemen City Supercharger lounge multiple times and I love it! During the day, the staff welcomes you and sells coffee. At night, you'll meet the night custodian who is busy cleaning the facility. Look for the code to access the building by clicking on the supercharger location on your nav screen.
It's a great place to relax and the Supercharging goes by quickly because you're so comfortable. Staff told me during summer they plan to have food trucks in the parking lot during the day. A must stop for any Tesla owner!