Some people have more trouble getting out there than others. Shy people or people who are true loners often seek safety by staying away from people. If they don't even work with many people, they will have a hard time sharing experiences with someone who is attractive to them and vice-versa. Elderly people or people who do not drive also have trouble getting out in most of the American world. Other people are isolated by physical disabilities, by geography, by abusive relationships, etc.
New mothers are often too tired or just too busy to keep up an active and satisfying social life.
Yet studies have shown new mothers are happier and more assured when they are able to meet with adults regularly, particularly other mothers. Once you have captured the attention of another person or vice-versa, you must expand on that original attraction. This expansion includes additional contacts and conversation. Someone must be on first for a friendship to develop. Certainly there is risk inherent in forming a friendship.