The heather-stepper, the horned stag,The antlered hart hard driven by hounds,Invading that forest in flight from afarWill turn at bay and die on the brinkEre ever he'll plunge in that haunted pool.-Beowulf
It is universally known that the greatest fear known is the fear of the unknown. As portrayed in the extract from Beowulf I typed above, a deer would rather die by hands of hunters than plunge in the lake where, rumor has it, lives a monster. Even though the monster is portrayed by Angelina Jolie in the movie, but that's another story.
It is ridiculous when you think of the things people do just because they are afraid. They pass up on great opportunities in life, good life lessons, a better income, a marriage, etc. And usually, there is nothing to be afraid of. The things we do, or rather not do are all dependent on our own insecurities and our stupidity. This is why opening one's mind is essential to opening one's life in terms of happiness and fulfillment. If you feel like you are stuck in a daily routine, unable to get out of it, do something immediately!
The best thing to do is travel, of course. It is also the most expensive things on my list of suggestions. However, nothing opens one's eyes as a trip to another culture. Still, if this is out of your reach, there are billion things you could do. Read a book that you would normally not read and find yourself surprisingly identifying with the characters. Even better, join a book club! Watch a film that you would normally never pick out at a rental store. Try a new sport. Meet new people. Do whatever you can to step out of your comfort zone and just... Breathe.