Haha. I was thinking the same thing.
On my landscape jobs (over a certain size anyway) i always give an ESTIMATED completion date,,,but i make it very clear that there are too many things that can change that,,,sick worker,weather,supplier delays,equipment break downs,etc,etc. Im sure its the same with any trade,whether its building a house ,or a chassis. Knowing this,and being on the "other side" is why i wouldn't rush,or hold their feet to the fire,when it comes to getting my chassis done.