Why do Programmers Hate Documenting?

As quoted by "David Clayworth" that programmers tend to loose the interest after solving the problem in hand. It happens with me a lot of time.

However, I tend to write the comment and function signature when planning a solution to a bigger problem. In comment I mostly add what I want to achieve from the function or code block. There are more chances of putting a comment while developing a new feature from scratch.