Murphy's law Design

Franky speaking, i not really understand what is  Murphy's design and i have read through from the internet, as i know Murphy's design is seem like '' anything can go wrong then it will go wrong ''. That's what i know from the internet. For examples, the time you need to launch a new site like yesterday, will be the one time it takes the whole 48 hours for the domain name to resolve. It's sound funny....