The Viral Video Formula

(Cartoon from HubSpot)
 
So is there a secret formula to creating Viral Videos? it's hard to say. You never know what people are going to enjoy. In my observations I would say a good viral video has these traits:

• Original - is this something that people have never seen before?
• Familiar - while original gets attention, don't overlook the nostalgia factor
• Humorous - few viral videos are Shakespearian dramas
• Short - most videos are a quick view on a lunch break or on the mobile phone between classes so the shorter the better

What are your favorite viral videos? What do they have in common?