I almost forgot something.  If someone has a serious grudge against you they could tamper with the car doors.  If your car has “pull” door releases, look carefully because someone might tape a razor blade under the release.  If your car has a button release, check for needles etc. taped to the button.  It only takes a quick look.

Moral of the story–don’t just do things without paying attention.  Personal security requires that you be alert.