AirWhaler will be a lot about earning and upgrading your ship's parts, weighing what your ship needs against what you can afford, weighing your ship literally against gravity...
So when it came time to enter and index a bunch of data (like price, mass, capacity, power) about a whole bunch of engines and gas tanks and rudders, I thought I might finally need to figure out what classes are for. After a day of experimenting, here is how I felt:
I just figured out what the heck classes are for in programming... even if I still can't quite explain what they are. 
I am riding high on defining my own variable types! I am in categorization nirvana!
Halleyscomet/Wakefield said: The more you use them, the powerful and wonderful they become.Just wait until you start building classes out of classes!
Oh totally! I had an Engine class with manufacturer, power, mass attributes, etc. and when it came time to weigh my ship, I wanted to look up its Engine by unique name in a list of engines and get the mass. Then I thought, hey why don't I just make a Ship class with an Engine sub-class (and a Gas tank and a Storage hold and a Crew quarters, etc) ?
All the information is there, however much of it I want to make up, it's glorious.
ship.engine.mass = 