slimmed down error handling intro

docs/errorhandling.rst

@@ -35,12 +35,7 @@ Error handlers
 
 .. versionadded:: 1.0
 
-Some errors are unavoidable because not only you make them.  Users might
-enter a wrong password or do something different in a way that you just
-cannot allow.  Or a third party service that your site relies on is
-unreachable while an user tries to do something with it.
-
-In those cases you might want to show error pages to the user in response.
+You might want to show error pages to the user when an error occurs.
 This can be done by registering error handlers.
 
 Error handlers are normal :ref:`views` but instead of being registered for

docs/upgrading.rst

@@ -44,7 +44,7 @@ See :ref:`error-handlers` for specifics.
     and therefore was replaced with the intended behavior of registering
     handlers only using exception classes and HTTP error codes.
     
-    Trying to register a handler on an instance now raises :exc:`ValueError`
+    Trying to register a handler on an instance now raises :exc:`ValueError`.
 
 .. _upgrading-to-010: