In this world, there are both extroverts and introverts. Even when it comes to introverts, you have the type who likes to be alone most of the time and does little communication with others, and you also have the type who likes to socialize but prefers close friendships, even if it's only with a few people, over socializing in large groups. I admit I belong to the latter type of introvert, preferring to have a drink or a meal with my few close friends than to have outings or parties with large numbers of people with whom I may only share superficial relationships. It depends on the person's nature and, as you've rightfully pointed out, peer pressure, especially when they are very conscious about how others perceive them and value them by how "popular" they are. Just a piece of thought from a semi-introvert like me.
Then again, it is good to have time for socializing, and time for solitude. Too much of either one, in my opinion, may not be good psychologically.