Some more stuff i just thought of:
- Refueling, that means all vehicles could run out of fuel and you must fill them up.
- Rent rooms in hotels, sleazy motels and such.
- Take a prostitute to your apartment/hotel/motel and just not do it in the car.
- Invite friends/girlfriends over to your house for party, movienight and so on.
- More interactions with the environment, such as much more open shops, bars, clubs, electronic stores and more.