Tweak end slide

data/DrivingCodeWithData.cakedata

@@ -307,5 +307,12 @@ is hard.
 That doesn't mean it shouldn't be done, but does
 mean it should be done carefully.")
   (slide-data :heading "In conclusion"
-              :body "Using data to drive code is generally useful.")
+              :body "Doing this is not hard,
+knowing when to do this, and to what extent,
+is hard.
+
+That doesn't mean it shouldn't be done, but does
+mean it should be done carefully.
+
+Using data to drive code is powerful.")
   (slide-data :heading "Questions?"))