Do you use your car as a mini storage space? Since your car is your second personal home, would you use it to store things you need to use or to hide some things like unauthorised purchases, or avoid all the clutter inside your car?
Like using your car to hide your "unauthorised" purchases from your wife, like golf clubs, electronic gadgets, etc.
Use it to store your kid's toys which they can play during journeys.
Use it to store your work related stuff.
Use it to keep additional clothes and shoes just in case.
Keep all the name cards in the glove box.