Chris Petrilli explains how simplicity is power:

When people are introduced to Smalltalk, they often come away a bit befuddled, and also feeling like some of their syntactic sugar addictions can’t be fulfilled. Take the wiley “case” statement that exists in many languages. Turns out you can implement it in Smalltalk via just simply extending the underlying classes. Poof! Try that in most languages and people will look at you funny. So far, Lisp and Smalltalk are the only two languages I’ve used that are so trivially extensible to meet new requirements. Others can be extended, but not so seamlessly.

Another example - look at how languages like Java and C# implement generics, and then consider that it's a complete non-issue in Smalltalk.