If there is one thing you can bet on, it would be this: A lot of interesting happens beyond your comfort zones. And the sooner you acknowledge it, the sooner you can take small steps or huge strides to explore the limits you may have set for yourself. With so many great reasons to do it, the only question is when you will finally break through the boundaries and experience life to the fullest.
Go somewhere not many people dare to go. Travel solo if you can. Go on an adventure packed trip that includes a wildlife safari somewhere in Africa. Explore cities and cultures of Asia. Visit as many places as you can in Europe and more. Traveling, especially if you are doing it alone with no one to depend on in unfamiliar places can be uncomfortable. But doing it is a great way to break free of your comfort zone. You meet new people, explore the unfamiliar, and gain new experiences you would not usually acquire by staying comfortably at home.
Keep your sense of adventure. You do not have to venture into distant and exotic places to infuse some adventures into your life. Sometimes all you need is to do something drastically different from your normal routines. Spend time away from work or anything that entails the use of technology. Go somewhere without using any navigational device, read a book, spend a quiet afternoon in a nature reserve, and more.
Set big goals. Dreaming big and setting seemingly impossible goals can be scary, especially if you think about all the work needed to accomplish it and the pain of failure. But it can also push you to achieve more than you think you could. Set your eyes on an ambitious project or goal that would consistently challenge you. Running an ultramarathon, writing a novel, and learning a language is just some big projects that require mini-goals to accomplish.