Finding Ourselves (Not as cheesy as the title sounds, I promise)

Today in my European History class we talked about the pessimism after World War Two. We were discussing psychology and discoveries and things and it got me thinking....how much do we really know ourselves if we are so constantly bombarded with propaganda and always told how to think? From the day we are born, morals are instilled in us. We are taught that stealing is wrong, sharing is good, and "nice" means treating others with respect. Doing otherwise is considered "wrong." What really is wrong, though? Morals are subjective. Morals come with religion. The world's morals are similar to most religions out there. If religion = morals, then what is really right and wrong? I'm a Christian, so I believe in Jesus and his teachings, but when considering these things I like to strip away any bias I have and only look at fact. If there were no religion, if there were no propaganda, if there were nothing to influence us in any way, what would we be like? If we had never developed the modern sense of right and wrong, where would we be? And how can we truly discover ourselves if we are constantly subjected to others opinions? We also talked about mass psychology, the psychology of a crowd. All of humanity is a crowd. Adolf Hitler showed us that under the right manipulation, humans are capable of doing unspeakable things. Even from half a world away, Americans didn't step in to do anything. The whole WORLD stood by and walked 6+ million people just like them die cruel deaths because of what they believe or what race they are. Now, today we think "well, I would never do that. If I had been there, I would have stopped it. I would have done something." You cannot truthfully say that, though. The German race is not to blame. One man did that. But I digress. My real question is, how do we know who we are and what we like if people are always telling us what to think? If we hear another person's opinion enough, we start to believe it ourselves.
Pizza tastes gross.
Pizza tastes gross.
Pizza tastes gross.
Pizza tastes gross.
Pizza tastes gross.
Pizza tastes gross.
Pizza tastes gross.
If I said this enough times, you would begin to have a lower opinion of pizza, no matter how much you like it. Same goes with rumors, the more times you hear something, the more you believe it. The truth is, we really don't know ourselves very well. How can we? We are a reflection of the time we live in and the culture we are exposed to. So now we must ask....how does culture come about?