'lightning Strikes Twice'
To go waaaay back to the "lightning striking twice" debate, you just have to look at physics.
Although modern buildings are an exception (and I will explain why), in the past it would become very difficult for lightning to strike the same point twice. Lightning is simply electrons that build up as clouds rub against each other (like static electricity...in fact...EXACTLY like static electricity). As these massive amounts of electrons build in a cloud, protons within the earth are attracted to them. They climb up towards the sky using the path of least resistance (like a tree, or a person holding a golf club), and when the attraction is great enough, the electrons come down in a bolt of lightning.
The electrons and protons come together and neutralize the attractive pull of each other (as well as usually destroying the thing the lightning hits). Thus, that area of ground no longer holds enough free protons to attract lightning. There will, however, be other areas that are still charging their protons, so when the next bit of electrons in the sky builds...
Modern buildings almost always have lightning rods attached to them. The purpose of a lightning rod is to get hit by lightning. They provide a metal route into the ground, insulated like high-voltage wires. This gives the protons a very good way to get very high in the air. A lot of protons can thus swiftly get up hundreds of feet. They attract more lightning strikes than the building would normally, but they almost always channel the energy into the ground, where it can't do damage.
Hope this clears things up, I didn't touch on everything, but it's a basic reasoning.
