This article is an excellent one from Craig Buckler. Happened to read this and being a developer myself basically, I could not help but admitting to all his points.
Read the article here: 10 Reasons Why Project Estimates Fail.
If you have more reasons to add? Please add those reasons as Comments to this post or Comments to the original post directly. Either way, I am too curious to know your views on this article.
send it to customer as guestimates.. thats what i do :)Arun