Sometimes, it's pretty difficult to be "on" for a group. Especially when it's equally easy to just mind your own business, and avoid the particular social situation all together. Although there's nothing wrong with being an introvert, some people might want to ring in the new year with New Years resolutions to become more extroverted. If you think about it, it's a solid resolution to have; it signifies that you're ready to put yourself out there, and speak your mind a little more than you already do.
Extroverts are known for being outgoing. Simply put, they thrive in social situations, and often have trouble being alone. They're sociable, friendly, and the person you wish you could be more like at every party.
Of course, introverts have their charm as well. They often have a bunch of long-term friendships, are usually pretty responsible, and are fiercely independent. But, sometimes, it's nice to just shake the feeling of, "I wish I was at home watching Netflix" whenever a social situation arises. Since as an adult, you'll be facing a lot of social situations.
Making a resolution to "be an extrovert" is bound to fail. Really, you don't want to change who you are entirely — you just want to incorporate activities into your life that'll make you feel a bit more well-rounded. Here are a few good ones to help get you started.