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 Michelle Obama giving a thumbs up (note the classic "NOT BAD" facial expression). This can be used as a reaction whenever somebody says or does something online that you agree with.