Think real hard about why it bothers you when a stranger says negative things about fb. Be careful about closing yourself off to those who take opposing positions. Egos will want to remain consistent with past choices, but the world evolves and changes constantly.
Shut off the ego and shut off the emotions. Listen to others opinions then go and do what you feel is right. Opinions are water under the bridge.
You shouldn't be tiring of any opinions if you are a serious investor. Many analysts have fb pegged at near $15. If they are all wrong, then you don't have to try to convince others that everyone is wrong, just go into the market and buy as much stock as possible and just wait for the efficiency of the market to catch up. FREE MONEY...if you're right :)