What do you think makes a good friend?

Undoubtedly, everyone makes friends with others. However, what makes the difference between someone you consider as friend and someone you consider as a good friend? In my opinion, I think a good friend to me should satisfied some condition as follow: They should be someone you can share your secrets with, often considers about you and willing to give sincere suggestion for you.
First of all, everyone has their own secrets, no matter it is about themselves or about others. I think people sometimes needs to keep it while sometimes it will be really hard to afford it by their own and will need others' opinion. When the later condition happens, we need someone we really trust to talk to and shared with. I remembered once when I was in elementary school. I was the only person who saw someone stole a ring of others' during break in class. At that time the whole class was full of anger and no one admitted when the teacher asked. I was so afraid of turning him in because I think he will be punished badly from everyone. I felt so bad and even had a nightmare that night. It was David, my best friend , found something wrong with me the next day and finally went to the teacher with me to tell the truth. Fortunately, the teacher talk with him in private and did not punished him badly afterward. Instead, she make a lesson to the whole class that we should not stole anything and we should be honest to ourselves. I really appreciate David for saving me from the worse condition.
Secondarily, a good friend should be someone who you can learn from and make you a better person. Undoubtedly, everyone makes mistake or will have several bad habits in their life and sometimes they will not be aware of it if no one points them out. When these conditions happen, we will need a friend who really cares about you to give you suggestion. For instance, I am a person who like to share foods with others. I remembered when I first arrived the states, I shared food with others as I used to do when having dinner. Not until my friend told me afterward did I know that Americans do not usually share food with others. No matter why they did not eat the foods I gave them. After the talk, I learned a lesson about the general table manner and I really appreciate he told me that.
In conclusion, I think a good friend should be someone who considers about you, share your secrets and willing to give sincere suggestion to you. Just as the phrases said, good friend is like a good book and they can taught you great lessons!