There are many reasons why people make or break meeting or completion times. Generally people make what is important to them, and miss that which they care least about. Business people use diaries to manage their time so they complete all their tasks and minimise catastrophes, just best time to learn this skill is as a student. Keeping a diary with a time planning format allows you to make things on time. It helps to carry your diary with you.
Some people feel like their life loses spontaneity.