Just ask one question. My friend asked me to sing. Should I go or not?

Such friends are really annoying. I don't think he attaches great importance to you, so don't care too much about him, just do your duty: for example, you don't have to call him when he asks you to sing (he won't answer anyway). If he asks you to go, go. If you are not invited, don't include it in your life plan, because don't pay too much attention to it. On the other hand, if you ask him to sing, you should make a plan and ask him out on time. If he stood me up, forget it. Don't take it too seriously. Generally speaking, it is his business to be a friend, not all his business. This is only my personal suggestion, for reference only.