diff --git a/src/ServiceManager.php b/src/ServiceManager.php
index <HASH>..<HASH> 100644
--- a/src/ServiceManager.php
+++ b/src/ServiceManager.php
@@ -146,9 +146,10 @@ class ServiceManager implements ServiceLocatorInterface
         }
 
         if ($this->allowOverride === false && $this->has($name)) {
-            throw new Exception\InvalidServiceNameException(
-                'A service by this name or alias already exists and cannot be overridden, please use an alternate name.'
-            );
+            throw new Exception\InvalidServiceNameException(sprintf(
+                'A service by the name or alias "%s" already exists and cannot be overridden, please use an alternate name',
+                $name
+            ));
         }
 
         $this->factories[$name] = $factory;
Allow merging Service Manager configuration

- Allows specifying a "service_manager" key in module / application
  configuration
- Configuration provided by a module is merged with internal
  services configuration
- During loadModules.post, all merged service configuration is then used
  to configure the ServiceManager
  - Thus, modules and/or application configuration can override
    services! EXCEPT for services in the default configuration...