My car stopped in the middle of the road

After band practice at Fortbend church today, I drove home on Hightway 6.  At a traffic light, my car suddenly shutdown.  There was no electricity.  Nothing.  Just died in the middle of the road.  I was totally in panic mode.  Luckily, a total stranger came by and helped me pull my car to a safer place, and suggested me to take a look at the battery connection.  It turned out that the connection was indeed kind of loose.

Since I was the one was changed the car battery like a month ago, so it was pretty obvious that I was the one who didn't tight up the connection enough.

With the help of that stranger, I was managed to get the car running again, so I drove to the near by Walmart (only 2 minutes of driving time), pay $8 to buy a set of wrench, and used it to tight up the connection. After all, I need a set of that kind of tool in my car in case something goes wrong anyway.