It's uncomfortable. It's tough. And it's pretty much inevitable. That it, unless you're living a perfectly safe and comfortable life where every outcome is assured. The thing is, that type of life isn't going to help you grow, and it's probably not all that exciting.
The same holds true in running. We can run races we know we can finish, shoot for times we know we can hit. But what happens when we sign up for a race of a distance we haven't completed before? What about setting a time goal that we're not sure we can reach? It's a little bit scary, especially if we share those goals with other people who will then know if we failed. If we can't finish or miss our time we're going to be disappointed. However, maybe that disappointment is what we need to fuel our next challenge, to make us hungry to achieve more.
I'm not advocating for setting crazy and outlandish goals. If you’ve only run a 5k, 100 miles isn’t the next step. If you have a 4:00 marathon PR, your goal shouldn’t be an Olympic Trial Qualifier. The point isn’t to set impossible goals, the point is for them to be just far enough out that they make you stretch to achieve them.
Once you set that goal, put a plan in place to achieve it, and then work your tail off to get there. Even if you fail you’ll be better for the process, and ready to set your next goal.