Electric charge build up and dispersion through mediums?

[Ntstanch]

If you sport some X-mas grade wool socks in the typical striding motion across a carpet floor... what causes that build up of charge to stay in the body and leave in such a (seemingly) similar fashion to lightning dispersing into the ground when it doesn't just "wind down"? My best guess has to do with the water molecules in the body and mediums which allow for the transfer of the built up charge. I.E. - the wool socks are in general efficient at creating static charge and this is passed through into the body at a certain efficiency. Or something, I'm in no way certain regarding any of it.

The proper circumstances for the charges dispersion in the form of a shock is what I find the most interesting. Which elements allow the charge to flow with certain efficiencies into and out of one another, how mutual this is, if it can behave backwards (the door shocks you) - etc. This post is more a request for a good source of information regarding the chem physics, but I'm a fan of as much information as possible.

 

[Drakkith]

The wikipedia article should answer your questions for the most part.
Here's the link: http://en.wikipedia.org/wiki/Static_electricity

Take a look at the causes section, specifically the first one, Contact-induced charge separation.