Two times to make the same fault:microphone and key of the car

When I was little, I have been told that do not make the same mistake for second time.
Now I am about 30, but this thing happened again.
When I tried to use my microphone to talk with my friend through skype, I found the microphone does not work, after hard thinking and trying, it still didn't work, how sorrow I am!
After one hour, when I picked the microphone without hope to make it work, I found that there is a little switch on it, and marks of "on" and "off" are listed aside, I pushed the switch from off to on, to my surprise, the microphone worked!
This made me to get the impression that people can never think completely enough! and I thought of one thing happened when I still was a master student in the Northwestern Industrial University. One day, my boss asked me to fetch a piece of file from his car and handed me the electronic key, I thought that the principle is simple and I have seen many people use such a gadget, so I said I can use it, do not worry.
But when I go downstairs, I found that I cannot make the electronic key work, so I had to open the door of the car with the iron key along with the electronic key.After going upstairs, I told my boss that the key does not work, he just gently showed me the switch on one side of the electronic key, which is marked "on" and "off", I was so ashamed.
That story happened six years ago, after so long time, the same fault is made again! It seems that we should remember more mistakes and lessons we have gotten, and be careful!