What makes a video go viral? This is what we at Silver asked ourselves as we took a look at the most shared viral ads of 2015.

To help make our choice a bit easier, we decided there were three qualities that a viral video needs to make the list.

Pull at the heartstrings. Emotions are a universal language we can all understand. A strong emotional message gives viewers something to relate to. And emotions have a strong tie with memory and recall, which is good news for marketers.
Be Relevant. The video needs to be about something most people would be interested in. Popular trends can be great for creating intrigue, but there are always certain topics with timeless appeal. And if this means adding a puppy to your video, we’re all for it.
Encourage the viewer.  A viral video should make you want to act. At the very least, this act can be to share it with your friends to inspire them to be better. Or, it can change the course of your day and how you treat others.

Now, here are our picks for the best viral videos of 2015:

No one should have to be alone. – 693,343 shares

“What’s his name?” “Robert.” – 2,119,279 shares

Children get it. – 2,365,612 shares

Everyone needs a best furry friend. – 3,021,499 shares

Friends Furever – 6,432,921 shares