One way or another fear itself motivates everyone. It causes people to recoil in horror or lash out at everything around them. It causes people to break down or build up. It all really depends on the individual in a given situation and how they handle it. You can embrace things or fight them and either one can be right or wrong at any given moment.
Fear of the unknown- Much like a fear of change that grips people when they are faced with something new, a fear of the unknown usually causes two distinct reactions. They either attempt to avoid it and or altogether pretend that this unknown thing doesn't exist or they lash out at the unknown with resentment. Either way, the fear of such a thing has motivated the individual with whom it has come in contact with.
Some people will go to any end necessary to avoid the unknown. Dig themselves into a rut and refuse to except anything new within their protected walls. But somewhere along the way, something find it's way into your bubble and you will have to deal with it. How you do such a thing is in the end entirely up to you.
Fear of Failure- This is not altogether an uncommon fear, in fact it is somewhat natural to fear failing. It is a harsh reality of life and a bitter pill that too many people have had to swallow. This fear can create people who are afraid to move forward because they do not want to feel the pain of failure. These people rarely manage to go as far as they should for the simple fact that they don't take the chances that would lead them to success in order to avoid failure.
Of course there are also those that manage to overcome their failure and use it as motivation to move forward in their lives. Not everything is meant to be, but in some ways I feel that everything does happen for a reason and that includes failure. It's not always a bad thing, just a tough lesson that makes us stronger when we get up and brush ourselves off again.
Fear evokes a reaction from everyone whose path it crosses. Fear itself is not exactly a bad thing, in fact it's quite the logical response to a given stimulus. But no matter what your fears are in this life, the most important thing is keep them from crippling you. You can't go anywhere in this life without moving forward and that's just a fact. Use fear to your advantage, it can be done. No one on Earth is truly fearless, there are just people that control their fear rather than allowing fear to control them.