There are times in your life when you will not win. You will not accomplish your goal. You will not succeed. I'm not writing this to be a downer, I'm simply stating the facts. You can't be good at everything and you can't please everyone either. That's okay though. I'm letting you know that it is perfectly fine to fail. It's easy to be positive when you're succeeding and everything is going well for you, but it's significantly more challenging to stay positive when things don't pan out the way that you expected them to. Your true character is shown in how you handle yourself when you don't get what you want.
Not making the sports team you tried out for, getting a bad grade on a paper, or losing an election can really shake you and hurt your self-esteem... if you let it. Rejection is one of the worst things to deal with, but it's a part of life that I believe is quite necessary. Of course, in the moment, when you first get your paper back and it has a big, fat C written across the top, you don't feel that way. However, when you do fail, it is important to reflect and think about what you can learn from your failures.
Turn your failures into lessons and grow from your mistakes. I'll never forget my first research paper I wrote freshman year that got a 75%. You're probably thinking that I'm a grade grubber because a C is a perfectly acceptable grade for your first college research paper, right? For me, getting a C was the equivalent of getting a 0%. It was so unexpected for me, so I asked my professor to go over the paper and explain how I could have improved it. After meeting with her, I instantly became one of her favorite students in that class and she was so impressed that I even cared about my grade on the paper.
The next paper I wrote for her, I worked my butt off because there was no way I could get a bad grade in a freshman English class as an English major. I spent hours in the library and even took it to my advisor to look over it... where she tore it to shreds but helped me a lot. I ended up getting a 100% on that paper and my professor read it to the class. Ever since then, I've had a great relationship with that professor, and I finally figured out how to write a quality research paper.
This is just a little example of how something that may seem like a failure is actually just a learning opportunity for you to grow from. It's never fun at the time, but something good can come from any failure if you decide to evaluate it and learn from the experience. If nothing else, you'll be a little thicker skinned by the end of it.