A pleasurable pastime it is. Browsing through Garfield comics and smiling at the nice gestures Jim Davis draws to convey Garfield’s communication. I created a couple of lists ealier (here and here), and here is another list:

Polite palm out point & reproach with arms on hip
Here’s me! arms wide & reproach with arms on hip
Thumb pointing backward
Challenging grin
Jon’s angry glance and Garfield’s defensive point
Duh!