I think that there is such a thing as herd mentalilty.
We do what our social contacts do and talk about.

I believe that people have finally stopped talking about real estate at dinner parties and backyard BBQs. Do people still brag about and try to convince their friends and relatives to buy real estate?

Here’s a study about how people subconsciously imitate their peers. Not surprising at all. Monkey see, monkey do.
http://www.signonsandiego.com/news/health/20070725-1426-bn25weight.html