For instance, an Engineer "is a" Person who "has a" Job. They tend to be statically and early bound to their properties and functions, and if they need to change jobs, they have to be recompiled, which is expensive. If you ask them to do something that they don't know how to do, they will probably try, though may fail spectacularly segfault style, taking the whole program down. Engineers are written in C++.
A graphic designer is a Person who may or may not have a Job, or may intermittently have something that fulfills the function of a Job without being a Job itself. They tend to be dynamically late bound to their properties and functions (just ask my wife, who does a lot of freelance and contract work). They are written in Ruby.
Engineers tend to have very well defined ideas of what is public and private, whereas designers wear their heart more on their sleeve. Entrepreneurs may have a public interface, but they tend to be so outgoing as to not have private data - they may have public knowledge that is simply inaccessible and out of scope.
It might not be the most correct train of thought, but it is amusing, so long as you don't take it too seriously.