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 Jonah Hill sitting in the crowd at the Oscars. The cut throat motion that he's making makes this a great reaction gif to use whenever you want somebody to "cut it out" or "don't go there".