A practical friend is someone you are generally around, and so it is best to be friendly and associate with them occasionally. An example of practical friends can be your high school classmates. They are practical friends because they have been with you every day for many years, and yet as soon as one of them graduates, they are no longer likely to interact with you. From my personal experience, I had many friends with whom I went to elementary school and then to high school. I had known some of them for over ten years and yet, as we all graduated and attended separate schools, I had not heard from them. They were convenient friends back then, but once we broke up and there was no longer anything connecting us, we wouldn't be able to associate. The majority of practical friends are only useful at one point, but are probably not true