Feature engineering Memes

When you learn decision trees in your first ML class and suddenly think you can classify the entire animal kingdom with two features. The tree confidently declares that anything with ≥2 legs but <3 eyes is either a spider or a dog. Naturally, our penguin friend here gets classified as a dog because it has 2 legs and 2 eyes. The logic is flawless, the execution is perfect, the result is... well, technically a dog now. This is what happens when you oversimplify your feature set and have the confidence of someone who just finished chapter 3 of their machine learning textbook. Sure, the decision tree works exactly as programmed, but maybe—just maybe—we needed more than "number of legs" and "number of eyes" to distinguish between spiders, dogs, and flightless aquatic birds.