"A lot of what we decide is influenced by what’s going on around us" explains Legg Mason Capital Management's Chief Investment Strategist, Michael Mauboussin.
I'm sure we think we are all logical and rational but again some observations point to the contrary.
On a bigger scale, those around us shape the way we think and live - skewing our decisions to a particular direction without us being conscious that it's happening.
I'm guessing the only way to fight is awareness. And the most valuable - self-awareness.