Understanding object-orientated programming
Even if you've never thought about it, we are always classifying things and grouping things together using abstraction. We can talk about vehicles, and we have shared knowledge of what is included in this group. Cars, bicycles, boats, and airplanes are, while pencils, ducks, and swimsuits are not.
I could say, I need to go to town. Can anyone lend me a vehicle?
You will interpret this in such a way that the actual kind does not matter, but it must be something that can transport me to town. It could just as well be a car as it could be a skateboard.
Grouping things into these abstractions make our lives easier as we will not go into details every single time, we talk about something. I can ask for a vehicle instead of describing that I need a device that can transport me from my current location to town...