1. Good friends keep confidences. This doesn't mean that friends don't ever gossip about each other. Some gossip is harmless. Two friends talking about how they don't like another friend's hairstyle or boyfriend is harmless gossip; it's just the sharing of opinions between two people. On the other hand, repetition of a secret told by one friend to another is a betrayal of confidence. Such people should not be kept as friends; but, it's important to remember that if you don't expressly say "this is not to be repeated," the other person may not know that he/she is hearing a secret. Different people have different opinions on what should be private and confidential. Don't assume your friends view secrets the same way you do. If you want to speak in confidence with someone, you must make it clear that confidentiality is your expectation.
2. Friendship requires effort just as a romantic relationship does. Someone who expects his/her friends to take the initiative and make the social plans is not a good friend. All relationships involve mutual obligations and responsibilities. If someone you have been considering a friend never initiates social activities with you, drop that person. She or he may be responding to your social overtures due to enjoying the attention, a symptom of narcissism. Or, the person may be a passive personality and in a crisis, these people cannot be relied on--which leads to my next point:
3. A real friend is someone who is there in a crisis. Many people are party friends or what used to be called "fair weather" friends. Unfortunately it's often difficult to know who these people are until a crisis occurs. A real friend is someone who would take you to the hospital in an emergency, and who will ask you what you need if you are sick or in a crisis.
4. A good friend takes your side in a conflict but also tells you the truth when you're wrong. A sad and not uncommon situation is when someone who's getting a divorce is abandoned by "friends." An advantage that single people have over married people is that single people never have to question whether someone socializes with them because the person likes their spouse.
Real friends also tell friends when they are wrong. Sadly, this sometimes leads to the end of a friendship, because we are living in an age of entitlement in which many people don't believe that they are ever wrong and react with rage when the possibility is mentioned (see my previous post on Narcissistic Personality Disorder). But, there can be an upside to this: Telling friends your honest opinion when you strongly believe the person is making a bad decision is a good way to get rid of friends with pathological narcissism. Ultimately these people don't make good friends, so it's best to get rid of them sooner rather than later. On the other hand--
5. Offering a lot of unsolicited advice is a good way to annoy your friends and may eventually lead to the loss of friendships. Although it's important to warn friends about bad decisions--as I mentioned in point #4--friends who are subjected to repeated unsolicited advice may feel condescended to or may experience the friend as "bossy." Sometimes a good way to offer "advice" is to relate a personal experience: "When I was in that type of situation what I did was..." This sounds a lot better than "You should...." The fact you have had a similar experience lends credibility to your advice and sounds more genuine. Similarly one could say "If it were me in that situation what I would do is..."
6. Good friends aren't leeches. Borrowing money from social connections isn't as common as it once was, perhaps because today, as compared to previous generations, debt through credit cards, home equity loans etc. is more common. Today's leech is more likely to be someone who asks professional friends for extensive professional advice. As a health care professional I have been subjected from time to time to requests for feedback on extensively detailed personal problems from people who I would call social acquaintances. I don't do therapy with friends or social acquaintances, as it would be inappropriate. (On the other hand, I can give general advice on where and how to seek help). Similarly, stockbrokers and other financial professionals are often pestered in social situations for stock tips and free investing advice, and lawyers may be asked for free legal advice. The message this behavior gives is that the person is trying to leverage a social situation to get something for free that ordinarily costs significant money. A better way to benefit from friends with professional expertise is to ask them for a referral to a trusted colleague or to another type of resource.
7. Conversation is a give-and-take. Friends who are "good listeners" might actually be wondering when you're going to pause for breath or ask them what they think. On the other hand, someone who never shares his/her thoughts and experiences may be viewed by others as aloof, boring, passive, or possibly hiding something.
8. Friends don't invest the same feelings into your personal accomplishments and daily triumphs as you do. A patient told me a funny story once about a friend who wanted his friends to "attend" a virtual ceremony involving his new baby. Of course many people want to go to baby showers and similar events. because those are parties that often involve food and drink as well as socialization. That's quite a different experience from watching your friend's ceremony on your cell phone. Many people today are confused about the differences between actual socialization and exhibitionism/voyeurism accomplished via technology.
9. Good friends are on time, most of the time. Constant lateness is a sign of disrespect for other people. Even people with ADHD can learn to be on time.
10. Good friends can both give and accept gifts, but don't judge relationships by materialism. Someone who has difficulty accepting gifts may have a cynical or even paranoid outlook on life, believing that gifts are only given to obligate the recipient to reciprocate or do something else. It's true that there are some people who give gifts for such reasons, but those people usually make themselves obvious in other ways. Someone who doesn't give gifts on occasions that demand them may be immature or self-centered. On the other hand, narcissists sometimes give very expensive or ostentatious gifts to prove their status, and some people give expensive or excessive gifts because deep down they don't believe they are loveable, and instead believe that they are only appreciated for material things. The best people give ordinary gifts out of genuine affection without expecting anything in return, and likewise, accept gifts without seeing agendas behind them or believing that an exact reciprocation must be made.