Murphy's laws of piping - Millimeter ??!

In my project, I was dealing with stainless steel piping, glasswares, MS piping etc etc. all made by different vendors.

Many a times, they did not match. !!

Murphy's law holds good in piping as well!!
Thought murphy hasn't formulated this law, I will do so for him :D

" Law 1. If you construct any type of piping, you will miss dummy flanges at points, triclovers will not fit, flanges will not match and any such thing if it can go wrong, IT WILL.
Law 2. At the top of it, if there can be a way in which all these things can go wrong, it will happen in the worst possible manner.

Law 3. If you are fully cautious about all these laws, and are experienced, your piping will differ by what is called as millimeter :D "

This makes me realize the value of a millimeter.