Overfitting Symptoms

Warning: Overfitting is a serious condition.

Here are some symptoms of overfitting:

Unusually high accuracy on the training set
Unrealistic model complexity
Model performs well on overly complex models
Model performs poorly on underwhelming predictions
Unexplained behaviour on unseen data

(Note: Overfitting is a real problem in machine learning, but this page is meant to be humorous and not a serious resource for diagnosis or treatment.)