It’s my stock and I love it

A Mathematician Plays The Stock Market by John Allen Paulos ; a must read if you're going to dabble (don't dabble!) in the stock market. 

Sheep on the dike by Dagebüll
Avoid behaving like sheep when investing

The “endowment effect,” ... is an inclination to endow one’s holdings with more value than they have simply because one holds them. “It’s my stock and I love it.”

and

If enough people suddenly wake up believing in a stock, it will, for that reason alone, go up in price and justify their beliefs further...