Fear

I have a hard time understanding fear. Why people live behind it, in it, do everything they can to avoid it, but in reality, they actually allow it to control them. I understand being afraid, especially of the unknown, but once you realize that fear is what is messing with your mind, then why do some people say, "Okay, I'm not going to let that stop me." and others say, "I need a minute, wait, I can't handle this, or NO!"? What do they think is going to happen? What is the worse thing that could happen? I know people that won't say how they really feel, positive or negative because of fear. They won't try new things or go somewhere different out of fear. They won't put themselves in a certain situation, not because they might die, but because they might be uncomfortable. As a person that wholly believes in biological instincts, how can allowing fear of things that are not comfortable or known be beneficial? Why do people care so much about what others think, not being inconsiderate, but not doing what you want or saying what you want because of it? I cannot be a person that is controlled by fear. I cannot enable others that are controlled by fear. I can hardly stand being around them. It's going to be so hard "helping" others who are afraid of everything. I wish I could empathize.