Act Like You're Just a Side Character
I might be sounding like a bit of a hypocrite here, so let me explain.
Previously, I wrote on the importance of treating yourself like the main character. Read more on that here.
Well, in the interest of keeping everyone from going on massive ego trip, I have to deliver some bad news. You're just a side character in everyone's story. Now, this shouldn't be a cause of great horror, nor a great surprise to many. While you do get the right to be your main character, it should follow that everyone else gets the same privilege as you. So, while you can keep on treating yourself like the famed adventurer you are, let's look at why it's important to act like you're just a side character.
First and foremost, it keeps you humble.
Nobody likes the attractive popular kids in all those high school movies. They're jerks. No one likes a narcissist. When people become enamored with themselves, they become a burden to others.
That's the weird paradox of selfishness. The more we become turned in on ourselves, the more of a burden we become to other people. Which is why it's important to act humbly. Now, I wish to dispel a popular conception of humility. True humility is not denying things you're good at, or taking credit for good works that you've done. It's recognizing that those works or talents that you have don't define you, or make you more of a human being than someone else.
Humility is thanking people for the compliment, and moving on.
You're allowed to recognize your own talent, but you cannot become obsessed it. No one (or at least very few people) hone a skill just for themselves. Why read thousands of pages of knowledge if you aren't going to share it with other people? Humility is recognizing that we all exist for one another, and that are talents and resources are meant to be shared.
Another thing worth noting, being a side character is the most important role you can play for another person. What's Luke without Han and Leia? Or Harry without Ron and Hermione? No main character completes their heroes journey alone. We all depend on one another. We all should be a Samwise Gamgee to each other. Always willing to carry the other person forward, even when their own two feet fail.
Alright, I might've gotten a little carried away with the references there. Mea culpa.
That's the role of the side character. People don't need someone trying to hog the spotlight in their lives. Plenty of other life events, and I'm sure plenty of other people will be doing that to your friends and associates. The least you can do for other people is allow them the lead role in their own play, since ideally they will be doing that for you as well.
Side characters are what breathe life into a story, and populate worlds with interesting casts of characters. We are these roles to each other. So we might as well be the positive and fun side characters. We've all heard the term "Negative Nancy,"* it's a phrase understood by most who hear it. Most people in their experience can name someone in their life that plays that part.
What if it's you?
Only you have the power to retire that role, and audition for a new one. We might all be main characters, but we aren't directors. We can't fire people we don't like. Well, sometimes we can, but I am not so much of an idealist that I believe people have the power to cut all negative people from their lives, which means the responsibility falls back on you, on us. It's our job to make sure we are not playing the negative roles in other peoples' lives. Everyone could use another Samwise. Everyone could use some comedic relief. Be that for each other.
Life is a stage, and we all get to occupy it. From where we're standing, it looks like the spotlight is hitting us, but if we were to turn our heads, we'd see everyone has their own individual spotlight. Life is one big drama piece, and if we want the show to be a success, we all have to play our parts well. That's our responsibility. So when we're at center stage, we need to make sure we're ready to carry the show...
...and when you're dancing in the background behind everyone else, you need to make sure you're in step with the rest of your cast. It's inescapable.
Life is a blended role, of main actor and supporting cast. Sometimes we're playing both parts at the same time. Some people will occupy life's spotlight more than others. We aren't all going to be president, king, or rock star.
So whatever our roles are, when we find them, we need to play them well.
St. Therese of Lisieux when observing the variety of saints God has called, commented, "I understood that if all flowers wanted to be roses, nature would lose her springtime beauty, and the fields would no longer be decked out with little wildflower." 
When we approach life like this, we thrive.
Not perpetually coveting what other people are or how "important" they may be to society at large. The auctioneer at the beginning of the musical Phantom of the Opera is never seen again after the opening scene, yet the tone could never be set without him. We are horrible at seeing our own significance, and constantly need reminded that we are.
So, let this be your reminder for the day that you actually matter, and the part you have to play can only be played by you, and it is a part meant to be played for others.
*No offense to people named Nancy.