Before discussing advantages and disadvantages let's see what friendship means without understanding friendship we can't understand whether it is advantageous or disadvantageous.
Do you really have a friend? If I am your friend and you want to be alone, what am I to do? Chase you, get stuck to you or allow you to be alone. Do we really have friends? Somebody has said that a person is worth being with if you feel alone in his company. Only that person is worth being with. That's the test.
Do I feel crowded with this person or do I feel peaceful, alone in his company? That's your real friend; the one who allows you to be alone. Not somebody who starts cluttering your mind. What do your friends do? Ask yourself. Are they a crowd or are they a peaceful influence?
Friend by definition is a well-wisher. A friend by definition is a man who would celebrate if you are improving. Not a man who would be jealous and irritated seeing you walk the path of liberation. He is not a friend at all. But don't condemn him, because if he is not a friend to you, firstly he is not even a friend to himself! He is his own enemy, how can he be a friend to you? We make friends with so many people, without even asking, "Is that fellow a friend to himself first?" He is his own enemy, how can he be my friend?
The one who does not know what is good for him, how will he know or like what is good for you? He is bound to resent it. How can you give importance to their resentment? If somebody is really your friend, he would not want to be pleased. If somebody is really your friend, he would see the truth in your eyes. He would not say that kindly act as per my beliefs and convenience. He would not say that do not tell me things that I do not want to hear. And if there are such people in your life who run away from you on hearing the truth, kindly let them run away, because they were anyway never in your life in the first place.
The only true relating that is possible, is that of friendliness.
Trade is based on 'give and take'. Relationships are based on 'love'. And love is giving. You don't expect a 'take' in love. This 'give and take' is violence, because if there is 'give and take', you always want more 'take' than 'give', as happens in business. Right?
In love, you don't bother about taking. When there is a need to take, you just take. Have you observed that with your friends? If you have really been friendly with someone, you don't bother too much about asking. If there is something kept on his table, do you seek his permission? If you seek his permission, then it is some kind of a business arrangement. No, relationships are not based on 'give and take'. The basis of relating is attention, presence and love. It is not 'give and take'.