“There have been studies that show when we are by ourselves, what is uncomfortable is the lack of stimuli, that you can’t rely on other people to shape your experience in a certain way,” Dr. Nguyen said.

Our aversion to being alone can be quite drastic: A quarter of the women and two-thirds of the men in a University of Virginia study chose to subject themselves to an electric shock rather than do nothing and spend time alone with their thoughts.

Why it’s good to spend time alone

An online survey called The Rest Test showed that the majority of activities people defined as most restful are things that are done solo.

Despite the social stigma and apprehension about spending time alone, it’s something our bodies crave. Similar to how loneliness describes being alone and wanting company, “aloneliness” can be used to describe the natural desire for solitude, Dr. Coplan said. Since we’re not used to labeling that feeling, it can easily be confused for, and feed into, other feelings like anxiety, exhaustion and stress, especially since “we might not know that time alone is what we need to make ourselves feel better,” Dr. Coplan added.

Enjoying the benefits of time alone isn’t a question of being an introvert or extrovert, Dr. Nguyen said. More consistently, people who value solitude and who tend not to ignore their own desires in the pursuit of pleasing others will find time alone more enjoyable, she said.

The freedom of not having to follow the lead of others, with “no pressure to do anything, no pressure to talk to anyone, no obligation to make plans with people,” is a great way to process and decompress, even for highly social individuals, Ms. Roberts said. It also helps us discover new interests and ideas without having to worry about the opinions of others — one study even showed that teens are less self-conscious when they’re alone.

“Cultivating this sense of being alone and making the choice to be alone can help you to develop who you are, your sense of self, and what your true interests are,” Dr. Grice said. Knowing oneself makes it easier to find other people who share your passions, and can improve your empathy. It can also help you re-evaluate “filler” friendships: relationships you maintain because you’d rather do anything on a Friday night besides staying at home by yourself, even at the cost of spending time with people whose company you don’t enjoy.