Idiom
It's easy to be wise after the event.
British, American & Australian, American something that you say which means that it is easy to understand what you could have done to prevent something bad from happening after it has happened.In retrospect I suppose we should have realised that she was in trouble and tried to help her but then I suppose it's easy to be wise after the event.People often tell me they'd never have taken out a loan if they'd thought about it more carefully - but it's easy to be smart after the fact.