Gif Central boasts hundreds of funny animated gifs. Only the best of the best make it onto this site, with most of them having an accompanying source. No tumblr-esque one-second-long disappointments. No obscure titles or descriptions.
This is an animated gif of a knight (John Cleese) tapping his hands excitedly on top of a castle. This can be used as a reaction whenever an argument breaks out between two people online. This is from the movie Monty Python and the Holy Grail (1975)