You shouldn't use your friend's account without their permission.
James' friend left his computer logged in to Twitter while he went to the bathroom.
James wants to tease his friend.
James installs an extension that makes all links redirect to the Rickroll video.
James uses his friend's Twitter account to announce that he's getting a sex change.
James' friend laughs, then makes James uninstall the Rickroll extension.
When James' friend sees what he did, he yells at James, getting them both kicked out of the library.