What is a good friend?

Hello everybody!
This is my second post and in this occasion, I write about the question: What is a good friend?
But first. What means a good friend?
I think that a good friend is a person that ever is with you, in the good situations and in the bad situations too, especially if you have a problem.
Also I think that is very difficult make good friends. Not ever that you find a friend, you will have a good friend for a long time. Some people have a lot of friends but this not means that all are a good friends.
The nicest thing that I ever done for my friends is when I dedicate all the time of the world to listen to my friends. Because I think that anything so "simple" to do, like listening to your friend, is very important to improve the friendship of both.
Well, as I wrote above, the characteristics of a good friend is to be a person that is always with you to help if needed.