Morning Scepticism: Falsifiability

What's the difference between how a successful but falsifiable theory and how a theory that's unfalsifiable look? To the casual observer both would be able to explain all data that came in, so decrying a successful theory as being falsifiable is dismissing it for being right. When it comes to evolution, it's often asked how it could be falsified - the contention that evolution falls into the unfalsifiable category and therefore not science. Yet there are many ways to falsify evolution, from mammals in the precambrian to genetic analysis showing that cockatoos are our nearest relative, there are any number of ways to falsify evolution. The reason it hasn't been falsified is that the theory is good, not unfalsifiable.