You should take an interest in your friends.
Rachel receives an email from an old friend, about her recent marriage and the fact that they are expecting their first child.
Rachel has to decide whether to respond to her old friend or not.
Rachel responds with a congratulatory email and asks her old friend if there is anything she could do to help her prepare for the baby.
Rachel decides that she doesn't have time to rekindle an old friendship and deletes the message, without responding.
Her friend will feel touched that her old friend still cares for her and Rachel will feel good that she is maintaining the relationship.
Her friend feels badly that Rachel never responded, and Rachel regrets that she hadn't made more of an effort to maintain the friendship.