In client work, I've built features that were supposed to be "smart", to save the user's time.

In client work, I've built features that were supposed to be "smart", to save the user's time. It's often turned out that the features weren't quite smart enough (my code is no DeepMind), and the user resorted to workarounds. In the end, the client requested more powerful manual controls instead of auto-smart-features.

If you're thinking of coding a complicated feature: Consider giving your users easily-accessible controls to do the job manually and see how they use it, rather than trying to anticipate their every need.