[yodsanklai]

When you share code with other people, "your" code gets updated continuously. In that context, you often want to know what motivated an update, and how it may affect what you are doing.

Consider a bug fix, you want to know what was the bug, and why the fix is actually a fix. This is complementary to comments which don't tell anything about the code evolution.

A good commit message can save a lot of work to your colleagues and even yourself in the future.