One of the biggest issues with OOP is that it’s hard ;) I gave up attempting to get good at it after trying to read Bertrand Meyers’ Object-Oriented Software Construction book. If I need to be able to keep 1300 pages worth of info in my head to write well designed software, maybe it’s the wrong approach.

If I had my druthers, I'd put the teaching-ratio of interfaces versus inheritance at like 95%/5%. Treat concrete inheritance primarily as a useful work-saving shortcut.

Basically, I'm one of those people who might unironically write `class DefaultDog implements Dog extends AbstractAnimal`.