One of the biggest things I learned from moving to New York is the fact that it's totally OK to do things by yourself. Most people are so against doing things alone, and have a very glorified idea of how the world should work by consistently having an entourage. But that gets old. Sometimes people don't think the same way as you, sometimes you want an evening to yourself because you live with three other roommates, and sometimes you can go to events alone and meet other people. Although it honestly rocks to have a group of people to do things with, don't be afraid to go do things alone! Sometimes you need it, and you deserve it.
Go alone to that cool restaurant you've been dying to try, but no one else is into Turkish food. I promise that you and the waiter will have a fabulous conversation and you will make up a fantastic story about how the old couple near you met. It's not awkward! Just enjoy your own company for a moment.
Go alone to the museum while everyone else you know is in class. It's a totally different experience, and you don't have to worry about who's having a good time, who's complaining about their feet hurting, who's tired, who's hungry, and the list goes on. Go for you and experience the art. (People in New York: Go to the MET during their late hours on Thursday or Friday when you have no plans and need to get away from your roommate. It rocks.)
Go alone on a run or a walk through Central Park. Especially on a nice day, it's more than easy to get completely lost in the colors of the leaves or the beautiful views of the city from the reservoir. Sit, relax, read a book. You won't regret it. Lay in Sheep's Meadow and stare at the clouds when it feels nice outside. The grass in Sheep's Meadow feels like you're lying on pillows.
Go alone on a spontaneous trip. If you're dying to go somewhere and can't find a travel buddy, book your ticket and go. You will enjoy the culture, sights, and people much more. Sometimes you can't find someone who is as passionate as you about New Mexico, but why should that stop you from going? It shouldn't.
Go alone to a movie. Sometimes you want to go see a foreign film, sometimes you want to go see a comedy. Just go! It's a perfect alternative to watching Netflix by yourself, and you get to go out into the world at the same time. You are being social while not being social. Plus, you can eat all of the popcorn and not worry about anyone else.
I know the concept of being alone scares people because society has made them feel like they have to look like they are with people at all times. Living in New York, it's rare to have an elevator to yourself, so you applaud the person sitting on the bench by themselves reading. If you want to do something but feel restrained by the fact that you have no one to do it with, try going alone. It's a very positive experience.