Sudo has an easter-egg that’s disabled by default. It can insult you each time you provide incorrect password. Just like that:

[sudo] password for agilob: 
You can't come in. Our tiger has got flu

[sudo] password for agilob: 
You do that again and see what happens...

[sudo] password for agilob: 
You can't get the wood, you know.

[sudo] password for agilob: 
Speak English you fool --- there are no subtitles in this scene.

[sudo] password for agilob: 
I think ... err ... I think ... I think I'll go home

[sudo] password for agilob: 
Where did you learn to type?

[sudo] password for agilob: 
stty: unknown mode: doofus

[sudo] password for agilob: 
Listen, burrito brains, I don't have time to listen to this trash.

[sudo] password for agilob: 
sudo: 3 incorrect password attempts

To enable this beautiful feature you have to edit sudoers file with visudo and add line

Defaults insults

Press `i` to start edit mode, type in the line above, press `Esc` and then type `:wq` to save it – just like you save files in vim.