While most expressions are true, lightning not striking the same place twice is wrong. In fact, the Empire State building is struck about 100 times per year.
Lightning striking the Empire State building(1)
Lightning is caused when there is an imbalance of ions between the clouds and the ground or whatever the lightning strikes. Nature, naturally, wants to fix the imbalance, and does this by passing a high powered current between the clouds and the object. The current is called lightning.
Lightning strike (2)
Bibliography:
Info:
Images:
2: http://farm2.static.flickr.com/1003/773233665_859aba00fe.jpg