How do you program differently in dynamic languages?

Question

How would someone who really knows how to take advantage of dynamic programming languages approach programming differently than someone working in a static language?

I

Answer 1

I think the most dramatic difference in choice of data structures.

In Java or C I define structs or classes very strictly. If I need to add a property, I go back and change the definition.

In Perl I'll just use a hash, and 'invent' keys as I code.