I am happy to answer your questions.

You should look at the person to see if he can bring you something. Whether it's wealth or a happy mood, as long as you feel that what he brings to you is more than what you lose, then it's okay. Otherwise, it is best not to contact you. But breaking the promise is up for debate. If something really happened, there would be no blame. There are also people who are too lazy and don’t want to leave when the time comes, so they break the appointment. You need to judge whether the person is helpful to you and decide whether to make friends.

I hope my answer solved your problem.