The moment you get married or start a new job you start losing some of your freedom to do as you please. A marriage requires you and your spouse to split responsibilities and that either one or both of you work. Marriage will make the possibility of traveling less likely and if you do it will be less often. You can easily go through college and work with little if any breaks in between and then when you least realize it you are well into your 50's or 60's and with very little exposure to the world. To live is to travel it opens up new worlds and ideas once you set sail.
2. Change Careers
You graduated college and after working a few years you realize you no longer want to do the same work anymore. It may be time to get another degree in an unrelated field or a degree that will complement the first one. It is ok to not get it right the first time around but even if you are you may need to change your career to advance to your next phase. Stop thinking that you need permission or that people will see you as a failure. Be kind to yourself there is no point to fake being happy at a job you no longer want.
Yes, it all comes down to one thing: risk. Make leaps in your life you don't need to follow what others are doing just to feel safe and secure. To become that person that you dream of becoming requires big moves and changes. As long as it's ethical and legal do it! Years from now you won't be thinking about the rejections and falls you had you will however regret being too safe.
4. Help Others Out
Nothing worse than a person that is self centered. Volunteer, give back and possibly learn a new trade in the process. Use your time wisely and let it humble you to serve others and realize that maybe you don't know it all. Build someone else up, focus on other people's needs as well. You don't always need to cash in on every endeavor you take on, you don't always need to get a thank you or get recognized for every act of kindness. Life isn't always perfect or fair but if we all try to get even and dish out what we get then this world becomes very unpleasant.
5. Talk To People
When was the last time you talked to a stranger at a social event or at the library? Some of us think that as long as we have the people that either our jobs, school, family or friends have introduced to us we don't need anyone else. We walk around protecting ourselves from the world. Most of what you need in life will come from people and not everyone you need is on your network yet. You need to go get them. Those new people the soft acquaintances are more likely to help you than people you know very well.