The NaN Identity Crisis

Ah, the classic NumPy paradox: np.nan == np.nan returns False. Because apparently even NaN doesn't want to be associated with itself. Just like that one developer who wrote this code and now refuses to acknowledge it in code reviews. The screaming title perfectly captures that moment when you spend 3 hours debugging only to discover your data analysis is failing because Not-a-Number isn't equal to... itself. It's not a bug, it's a feature – said no data scientist ever.