We're all wrong
The software industry migration away from Smalltalk to Java and .Net may be one of the greatest causes of lost developer productivity, although its impossible to quantify. I've never developed Smalltalk commercially, but I have played with it on numerous occasions, and the more I see, the more I like. It really was a language before its time.
Take for example, the hooking a GUI to a domain layer. You want a simple way to uniformly hook the UI to the domain layer, without leaking UI code into the domain objects. The Smalltalk way is this:
| aspect | aspect := AspectAdaptor subject: aDomainObject. aspect accessWith: #getSelector assignWith: #putSelector
The above code says: create an instance of the AspectAdapter class, assign it to a variable called aspect, and wrap it around the object referred to by the aDomainObject variable. Whenever you receive a request for data, call the 'getSelector' method of aDomainObject. Whenever the UI value is updated by the user, pass the new value to the 'putSelector' method of aDomainObject. As getters and setters in Smalltalk generally follow a convention, there's an even shorter way of writing the same thing:
| aspect | aspect := AspectAdaptor subject: aDomainObject. aspect forAspect: #iFieldName
Smalltalk is chock full of things like this, things that we threw out when we moved in favour of strongly typed, C-based languages.